UBZ-305M Operating Manual

This Operating Manual is intended to familiarize you with the unit, the requirements for safety, operation and maintenance procedures of the universal motor protection unit UBZ-305M (hereinafter referred to as UBZ-305M or unit).
During operation and maintenance, the regulatory document requirements must be met, namely:
- Regulations for Operation of Consumer Electrical Installations
- Safety Rules for Operation of Consumer Electrical Installations
- Occupational Safety when in Operation of Electrical Installations
Installation, adjustment and maintenance of the Unit must be performed by qualified personnel having studied this Operating Manual.
In compliance with the requirements of this Operating Manual and regulations the Unit is safe for use.
The Unit meets the requirements of the following international standards:
- EN 60947-1
- EN 60947-6-2
- EN 55011
- EN 61000-4-2
Abbreviations and Terms
Section titled “Abbreviations and Terms”| Abbreviation | Meaning |
|---|---|
| ARS | Automatic restarting |
| MS | Magnetic starter |
| PC | Personal computer |
| CT | Current transformer |
| LCD | Liquid crystal display |
| MNS | Minimum number of settings (it is used in phrases as MNS mode or MNS list) |
| Iсt | Rated current of CT (it is set when external CTs using; e.g., if CТ is of Т-0.66 300/5 type, then Iсt equals to 300 A) |
| In | Rated current of the motor; As a rule, this value of current is indicated on the motor nameplate, but depending on the operating conditions, the different value of current can be set |
| S.c. | Short circuit |
1. Application
Section titled “1. Application”1.1 General
Section titled “1.1 General”UBZ-305M is a functional analogue of UBZ-305. But as to connection with PC, UBZ-305M uses USB interface instead of RS-232.
UBZ-305M is designed for protection of induction motors with power of 2.5 to 315 kW in case of using the external standard current transformers with 5A output current.
UBZ-305M can be operated in networks both with insulated and dead grounded neutral.
The unit is of DIN rail design version.
UBZ-305M provides continuous monitoring of mains voltage parameters, current values of the phase (line) currents of three-phase electrical equipment for 400 V, 50Hz, and checking the resistance values of motor insulation.
UBZ-305M provides protection of electrical motors in case of:
- low-quality network voltage (unacceptable power surges, phase failure, incorrect phase sequence and phase “coincidence”, the imbalance of phase/line voltages, the reduction in the network frequency lower than the set one and (or) the increase of network frequency higher than the set value);
- mechanical overloads (symmetrical overload in phase/line currents);
- the threshold crossing of the negative-sequence current;
- unbalance of phase currents without overload associated with the insulation fault inside motor and/or the power cable (the comparison of current unbalance factor according to inverse sequence with voltage unbalance factor according to inverse sequence);
- the torque failure on the motor shaft (“dry running” for pumps) – protection based on the minimum starting and/or operating current;
- motor delayed start or rotor blocking;
- extremely low isolation between the stator and the motor housing (pre-startup check);
- ground fault of the stator winding during operation – ground leakage current protection;
- motor thermal overload;
- overheated windings (temperature of windings is determined using the motor built-in temperature transmitters or the temperature of the housing when using the external temperature transmitters).
For each type of protection it is possible to have banning and permitting of automatic restarting (hereinafter referred to as ARS) with load.
UBZ-305M provides for electric equipment protection by means of controlling the coil of the magnetic starter (contactor).
UBZ-305M detects motor currents when load relay is off (when the load relay is off and functional relay is in star-delta mode). In this case, UBZ-305M indicates the fault of external contactor starting the motor until UBZ-305M is turned off or control of motor currents is disabled when load relay is off.
UBZ-305M provides for electric motors control:
- using analog inputs “0-20 mA” and “0-10 V”;
- using remote control channels (USB and RS-485 interfaces);
- by buttons on the front panel of UBZ-305M.
Communication
UBZ-305M provides:
- Control and transfer of parameters via RS-485 interface in compliance with MODBUS Protocol, and
- Control and transfer of parameters via USB interface.
For UBZ-305M to work with PC, you can use the program “Control Panel UBZ-304/305”, published on the “Novatek-Electro” website (https://novatek-electro.com/en/software/control-panel-of-ubz-304305.html)
The Program “Control Panel UBZ-304/305” has been designed to monitor the status and collect data from UBZ-305M via USB or RS-485 communication interfaces (MODBUS Protocol).
The program allows you to save (load) various settings of the device, collect data and save them for further analysis. The saved data can be viewed as graphs comparing the parameters with each other.
The graphical interface of the control panel allows you to monitor the current state of various Unit parameters in real time. The flexible interface configuration permits you to adapt to the requirements of any user.
1.2 Operating Conditions
Section titled “1.2 Operating Conditions”UBZ-305M is designed for operation in the following conditions:
- Ambient temperature: from minus 20 to +55°С
- Atmospheric pressure: from 84 to 106.7 kPa
- Relative air humidity (at temperature of +25°С): 30 … 80%
If the temperature of the unit after transportation or storage is different from the temperature of the environment in which its operation is assumed, then before connecting to the mains keep the unit in operation conditions for two hours (because on the unit elements condensation may be available).
1.3 Changes in the Characteristics and Operation of UBZ-305M Depending on Program Version
Section titled “1.3 Changes in the Characteristics and Operation of UBZ-305M Depending on Program Version”If the software version is 10 or less, then changes in UBZ-305M characteristics and operation are not available.
1.4 Controls and Overall Dimensions
Section titled “1.4 Controls and Overall Dimensions”1.4.1 Design
Section titled “1.4.1 Design”Overall dimensions of UBZ-305M are given in Figure 1.1.

Figure 1.1 – Overall Dimensions of UBZ-305M
1.4.2 Indication and Controls
Section titled “1.4.2 Indication and Controls”Controls of UBZ-305M are given in Figure 1.2.

- Green LED “Function” is on when functional relay is on
- Green LED “Motor”:
- is on when load relay is enabled
- flashes if UBZ-305M is within hysteresis band when controlling using analog inputs
- Green LED “Y/△” is on when UBZ-305M functional relay operates in star-delta mode (see section 2.5.3)
- Green LED “TR” is on when UBZ-305M functional relay operates in time-delay relay mode
- Red LED “FAULT”:
- when load relay is off: it is on when UBZ-305M is in fault conditions (it flashes if after fault ARS is expected)
- when load relay is on: it flashes when the motor is in conditions of over-current or thermal overload but relay off time has not come yet
- Blue LED ”⇄” is on when data exchange with PC occurs
- Connector for UBZ-305M to a PC via USB
- Button UP – scrolling of displayed parameters in the parameter view mode and scrolling of the menu in the parameters setting mode
- Button DOWN – scrolling of displayed parameters in the parameter view mode and scrolling of the menu in the parameters setting mode
- Green LED “MMSP” is on when the relay is in MNS mode
- Button “WR/SEL” – parameters recording in the setting mode, switching over the group of displayed parameters in the view mode, reset
- Button “SETUP” – turns on the parameters setting mode
- Red LED “SETUP” is on when UBZ-305M is in the mode of parameters setting
- LCD
Figure 1.2 – Controls of UBZ-305M
2. Components
Section titled “2. Components”Delivery set is given in Table 2.1.
Table 2.1 – Delivery Set
| Description | QTY |
|---|---|
| UBZ-305M | 1 |
| Differential transformer (zero sequence transformer) | 1 |
| Cable for communication with PC via USB (type USB type A – microUSB type B) | 1 |
| Temperature transmitter (types: Pt100, Ni100, Ni120) * | 1 |
| Operating manual | 1 |
| Packing | 1 |
* delivered by agreement with the buyer for a separate fee
3. Specifications
Section titled “3. Specifications”3.1 Basic Technical Specifications
Section titled “3.1 Basic Technical Specifications”Basic technical specifications of UBZ-305M are given in Tables 3.1 and 3.2; specifications of contacts of built-in relays are shown in Table 3.3.
Table 3.1 – General Data
| Description | Value |
|---|---|
| Application of the unit | Switchgear and control-gear; induction motor protection control |
| Design (installation) type | DIN rail 35 mm |
| Protection level | IP 20 |
| Climatic version | NF 3.1 |
| Operating temperature range* | from minus 20 to +55°С |
| Contamination level | II |
| Overvoltage category | II |
| Rated voltage of insulation | 450 V |
| Rated impulse withstand voltage | 2.5 kV |
| Electric shock protection class | II |
| Wire cross section for connection to terminals | 0.5-2 mm² |
| Torque for terminal screws | 0.4 N·m |
*Note: It is allowed UBZ-305M operation at temperatures from minus 35 to minus 20°С; in this case the readings on display can be not available.
Table 3.2 – Technical Specifications
| Description | Value |
|---|---|
| Operating supply voltage, three-phase | 400 V, 50 Hz |
| Mains frequency | 48 - 62 Hz |
| Rated current of CT | 5 A |
| (Phase/line) voltage hysteresis | 10/17 V |
| Heat hysteresis, in % of accumulated heat in case of shutdown | 33 |
| Determination accuracy of trip threshold for current, in % of rated value, not more | 2 |
| Determination accuracy of trip threshold for voltage, V, not more | 3 |
| Determination accuracy of out-of-phase voltage V, not more | 3 |
| Voltage when maintaining serviceability: | |
| - phase voltage, when powered by one phase and zero wire is connected, V, not less | 180 |
| - line voltage, when powered by three phases, V, not more | 450 |
| Analog inputs: | |
| - input to connect temperature transmitter (types: Pt100, Ni100, Ni120), pc. | 1 |
| - input to connect temperature transmitter of PTC-1000 type, pc. | 1 |
| - three analog inputs for standard CT with 5A output (T-0.66 type or similar), pc. | 3 |
| - input to connect differential current transformer (zero sequence transformer), pc. | 1 |
| - input to measure current of 0-20 mA, pc. | 1 |
| - input to measure voltage of 0–10 V, pc. | 1 |
| Main outputs: | |
| - load relay – two groups of changeover contacts to control the electric motor starter | 8 A, 250 V at cos φ=1 |
| - functional relay – one group of changeover contacts (function of the relay is set by the user) | 16 A, 250 V at cos φ=1 |
| Permit according to temperature of temperature transmitters | 1°С |
| Power consumption (under load), VA, not more | 5.0 |
| Weight, kg, not more | 0.34 |
| Overall dimensions (H×W×L), mm | 91×157×58 |
| Position in space | free |
| Housing material | self-extinguishing plastic |
Table 3.3 – Characteristics of Built-in Relay Output Contacts
| Relay | Max. current at U~250V | Number of actuations ×1000 | Max. switching power | Max. continuous boosting AC/DC voltage | Max. current at Ucont=30V |
|---|---|---|---|---|---|
| Functional relay Cos φ = 0.4 | 5A | 100 | 4000 VA | 440/300 V | 5 A |
| Functional relay Cos φ = 1.0 | 16A | 100 | 4000 VA | 440/300 V | 5 A |
| Load relay Cos φ = 0.4 | 2A | 100 | 2000 VA | 460 V | 3 A |
| Load relay Cos φ = 1.0 | 8A | 100 | 2000 VA | 460 V | 3 A |
3.2 Measured, Calculated, Special and Service Parameters
Section titled “3.2 Measured, Calculated, Special and Service Parameters”Special and service parameters are intended only for transmission using MODBUS interface (RS-485/USB). Special and service parameters are given in Table 3.4.
Measured and calculated parameters the values of which are displayed on LCD display, limits of their measurements and accuracy are given in Table 3.5.
Parameter values can be transferred to PC connected to one of the UBZ-305M interfaces (MODBUS, USB). Parameter addresses are indicated in Table 3.5.
Table 3.4 – Special and Service Parameters
| Measurement functions | Range | Remarks | Address |
|---|---|---|---|
| Heat balance of the motor | The number 1100000 corresponds to 100% of accumulated heat at which the motor is switched off when the thermal overload protection is enabled (section 3.4.7) | Read-only parameter of USB, RS-485 interface | 73, 74 |
| Index of the last fault in the fault logbook | It varies from 0 to 49, increasing by one after recording another fault in the fault logbook. When the number of faults will reach 50, the count of faults will begin again from scratch. | Read-only parameter of USB, RS-485 interface | 75 |
Table 3.5 – Measured and Calculated Parameters
Currents
Section titled “Currents”| Measurement functions | Range | Accuracy | Mnemonic | Address | Data transfer units |
|---|---|---|---|---|---|
| Effective values of phase currents, A | 0.5 – 6300 | 2% | Phase i1, Phase i2, Phase i3 | 30, 31, 32 | The tenth of amperes. When working with measuring transformers with rated current over 100 A, the currents (measured and calculated) in addition to the zero sequence current (ground fault) are transferred via USB/RS485 in amperes |
| Effective value of positive-sequence current, A | 0.5 – 6300 | 2% | Positive si | 33 | |
| Effective value of zero-sequence current, A | 0.3 – 20 | 2% | Earth i0 | 34 | |
| Negative-sequence current (imbalance), A | 0.2 – 200 | 5% | Revers si | 35 | |
| Average current per each phase during the time specified in the parameter “Tm average I” | Average i1, Average i2, Average i3 | 36, 37, 38 | |||
| Maximum value of the average current for each phase obtained since the last download. Reset of all average values is performed by the button WR/SEL in case of displaying the maximum value of average current in any phase | <3 Iсt: 2%, >3 Iсt: 10% | Peak i1, Peak i2, Peak i3 | 39, 40, 41 | ||
| Motor starting current (average phase current) | <3 Iсt: 2%, >3 Iсt: 10% | Start i | 42 | ||
| Overload current (average phase current) | Overload i | 43 | |||
| Starting time, s (time from when all three-phase current will exceed 1.2 In and up to the moment when three currents will drop lower than 1.2 In) | 0.1 – 600 | Start time | 44 |
Voltage
Section titled “Voltage”| Measurement functions | Range | Accuracy | Mnemonic | Address | Data transfer units |
|---|---|---|---|---|---|
| Effective values of phase voltages (determined when connecting the neutral conductor to UBZ-305M), V | 100 – 300 | 3V | Phase U1, Phase U2, Phase U3 | 45, 46, 47 | Volt |
| Effective values of line voltages, V | 100 – 475 | 5V | Line U1, Line U2, Line U3 | 48, 49, 50 | Volt |
| Positive-sequence voltage, V | 100 – 300 | 3V | Positive sU | 51 | Volt |
| Negative-sequence voltage, V | 3 – 300 | 3V | Revers sU | 52 | Volt |
| Zero-sequence voltage (vector sum of three phase voltages divided by three), V | 3 – 100 | 3V | Zero sU | 53 | Volt |
Miscellaneous
Section titled “Miscellaneous”| Measurement functions | Range | Accuracy | Mnemonic | Address | Data transfer units |
|---|---|---|---|---|---|
| Time counter of motor operation, day | 0 – 999 | Time motor | 54 | ||
| Motor insulation resistance¹, MΩ | 0 – 19.9 | 10% | Insulation | 55 | Hundreds of kOm |
| Mains frequency, Hz | 45 – 65 | 1% | Frequency | 56 | Tenths of Hertz |
| Hold time before automatic restart², s | 0 – 900 | 1 s | End of AR | 57 | Second |
| Time to overload trip³, s | 0 – 600 | 1 s | Before OvL | 58 | Second |
| Waiting time after overload trip³, s | 0 – 900 | 1 s | After OvL | 59 | Second |
| Full power⁴, kVA | 0 – 5000 | 5% | Apparent P | 60, 61 | Dozens of Watts |
| Active power⁴, kW | 0 – 5000 | 5% | Active P | 62, 63 | Dozens of Watts |
| Reactive power⁴, kVAr | 0 – 5000 | 5% | Reactive P | 64, 65 | Dozens of Watts |
| Cosine of angle between voltage and phase current L1 | 0 – 1 | 5% | Cos A | 66 | Cosine × 1000 |
| Cosine of angle between voltage and phase current L2 | 0 – 1 | 5% | Cos B | 67 | Cosine × 1000 |
| Cosine of angle between voltage and phase current L3 | 0 – 1 | 5% | Cos C | 68 | Cosine × 1000 |
| Temperature of transmitter 1⁵, °C | minus 40 – 80 | 1°C | Temp dat 1 | 69 | 5000 – transmitter is off; 1000±10 – s.c. of transmitter; 2000±10 – transmitter breakout |
| Temperature of transmitter 2⁵, °C | minus 40 – 220 | 1°C | Temp dat 2 | 70 | |
| Current value at analogue input “4-20 mA”, mA | 0 – 25 | 2% | Input i | 71 | |
| Voltage value at analog input “0-10 V”, V | 0 – 10 | 2% | Input U | 72 | |
| Full electric power⁶, kVA/h | 0 – 200000000 | 5% | ApE | 90, 91 | |
| Active electric power⁶, kW/h | 0 – 200000000 | 5% | AcE | 92, 93 | |
| Reactive electric power⁶, kVAr/h | 0 – 200000000 | 5% | ReE | 94, 95 |
Notes:
- If the insulation resistance of the motor is more than 20 MOm, then the value indicator displays code “>20M”. When the motor is running (energized motor) the insulation resistance is not defined and the code indicator displays ”---” (when measuring circuit of motor insulation connecting).
- If ARS is disabled, the indicator displays “not”.
- If the time before shutdown by thermal overload protection or waiting time before permit to start-up is not defined (more than 900 s), then the value indicator displays code “undef”. If the protection function is disabled, the indicator displays “not”.
- If the power consumed by the load is more than 999 kW (kVA, kVAr), the values of power are displayed with MW (MVA, MVAr).
- If the temperature value exceeds specified limits, then the indicator displays the alarm code in accordance with Table 5.13. If the temperature sensor is disabled by software, then the indicator instead of temperature values displays “Off”.
- In excess of the energy meter of the value 200,000,000, the counter is reset and the energy metering will start from zero. Recording the current values of the energy in the non-volatile memory is performed every 15 min.
3.3 Programmable Parameters
Section titled “3.3 Programmable Parameters”Programmable parameters and their variation limits are given in Table 3.6.
Table 3.6 – Programmable Parameters
Real Time Setting
Section titled “Real Time Setting”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Set the current time | Real Time | Setting of current time and date (see section 5.3.8) | See Table 5.9 |
Transformers
Section titled “Transformers”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Rated output current of used CT, A | CT out i | 1 | 5 | 5 | 151 | |
| Rated current of CT, A | CT nom i | 20 | 800 | 100 | 152 |
Basic Parameters
Section titled “Basic Parameters”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Rated current of motor, A | Rated Inom | 0 | 630 | 0 | 0 – current is not set: UBZ-305M will not enable the load relay (see section 5.2.7) | 150 |
| Time during which the average current is measured, s | Tm average i | 10 | 600 | 60 | Time during which the average current is measured (parameters: “Average i1”, “Average i2”, “Average i3” of Table 3.5) | 153 |
Over-current Protection
Section titled “Over-current Protection”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Type of over-current protection | Type Imax | 0 | 5 | 0 | 0 – “Indep” - protection with independent time delay. Types with dependent time delay: 1 – “SIT”; 2 – “VIT (LTI)”; 3 – “EIT”; 4 – “UIT”; 5 – “RI”. | 154 |
| Actuation setting for over-current protection, repetition factor | Imax coef | 0.8 | 9 | 4 | Repetition factor is set relative to rated motor current (used at “Type Imax” = “indep”) | 155 |
| Current protection delay tripping, s | Imax delay | 0.3 | 600 | 10.0 | 156 | |
| Permit for protection operation | Imax protec | 0 | 2 | 2 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 157 |
| Sequence of tripping relative to overheating protection | Imax<>T | 0 | 1 | 1 | 0 – “On” – tripping regardless of overheating protection; 1 – “Ind” – if there is no overheating, then over-current indicating displays but load relay is not disabled | 158 |
Ground Fault Protection (for zero-sequence current – I earth)
Section titled “Ground Fault Protection (for zero-sequence current – I earth)”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Over-current tripping setting, A | I earth tresh | 0.3 | 10 | 0.5 | If not in MNS mode list: 0.5 at In≤50A; 1.0 at In>50A | 159 |
| Tripping delay, s | I earth delay | 0.3 | 2 | 1 | 160 | |
| Permit for protection operation | I earth protec | 0 | 2 | 2 | 0 – “Off” - protection is off; 1 – “OnnAR” - protection is on, ARS after tripping is disabled; 2 – “On AR” - protection is on, ARS is enabled | 161 |
Negative-sequence Current Protection
Section titled “Negative-sequence Current Protection”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Actuation setting, % | I2 rev tresh | 5 | 20 | 10 | Set as percentage of rated current | 162 |
| Tripping delay, s | I2 rev delay | 0.3 | 10 | 5 | 163 | |
| Permit for protection operation | I2 rev Protect | 0 | 2 | 2 | 0 – “Off” - protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” - protection is on, ARS is enabled | 164 |
Analysis of Causes for Negative Sequence Current Tripping
Section titled “Analysis of Causes for Negative Sequence Current Tripping”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Ratio of exceeding negative-sequence current factor to negative-sequence voltage factor | A-s I2 coef | 2 | 4 | 2 | 165 | |
| Permit for analysis | A-s I2 protec | 0 | 1 | 1 | 0 – “Off” - analysis is off; 1 – “On” - analysis is on | 166 |
Thermal Overload (Heat Model of the Motor)
Section titled “Thermal Overload (Heat Model of the Motor)”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Permit for protection operation | Termal OL protec | 0 | 2 | 2 | 0 – “Off” - protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 167 |
| Operating time of protection in case 2 time over-current, s | Termal delay | 10 | 120 | 60 | 168 | |
| Factor of time increasing if motor is stopped | Termal C stop | 1 | 4 | 1 | Compensation of cooling time increasing while motor is stopped | 169 |
Minimum Phase Current
Section titled “Minimum Phase Current”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Actuation setting, % | Imin tresh | 11 | 90 | 20 | Operation threshold for the minimum operating current protection, in % of installed rated one | 170 |
| Tripping delay, s | Imin delay | 1 | 100 | 5 | 171 | |
| Permit for protection operation | Imin protec | 0 | 2 | 2 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 172 |
Delayed Start, Rotor Blocking
Section titled “Delayed Start, Rotor Blocking”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Actuation setting, repetition factor | Start I Coef | 1.3 | 7 | 5 | Repetition factor is set relative to rated current | 173 |
| Delayed start tripping delay, s | Start I delay | 1 | 600 | 10 | Time of motor starting | 174 |
| Rotor blocking tripping delay, s | Block I delay | 0.3 | 300 | 1 | 175 | |
| Permit for protection operation | St/Block prot | 0 | 2 | 1 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 176 |
Voltage Protection
Section titled “Voltage Protection”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Minimum line voltage, V | Umin tresh | 270 | 415 | 320 | 177 | |
| Tripping delay for minimum line voltage, s | Umin delay | 5 | 30 | 10 | 178 | |
| Permit for protection operation for minimum line voltage | Umin protec | 0 | 2 | 2 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 179 |
| Maximum line voltage, V | Umax Tresh | 330 | 450 | 415 | 180 | |
| Tripping delay for maximum line voltage, s | Umax delay | 0.3 | 10 | 2 | 181 | |
| Permit for protection operation for maximum line voltage | Umax protec | 0 | 2 | 2 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 182 |
| Line voltage imbalance, V | Uimbal tresh | 15 | 120 | 35 | 183 | |
| Tripping delay for line voltage imbalance, s | Uimbal delay | 1 | 30 | 5 | 184 | |
| Permit for protection operation for line voltage imbalance | Uimbal protec | 0 | 2 | 2 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 185 |
| Permit for protection operation for phase sequence | Correct phase | 0 | 2 | 1 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 186 |
Motor Phase Loss with Current Control
Section titled “Motor Phase Loss with Current Control”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Tripping delay for phase loss, s | Phase LossT | 0.3 | 10 | 0.5 | 187 | |
| Permit for protection operation | Phase Loss Prot | 0 | 2 | 1 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 188 |
Frequency Protection
Section titled “Frequency Protection”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Minimum value of voltage frequency, Hz | Frequency Min | 35 | 60 | 49.7 | 189 | |
| Tripping delay for minimum voltage frequency, s | FreqMin delay | 1 | 300 | 10 | 190 | |
| Permit for protection operation for minimum voltage frequency | FreqMin prot | 0 | 2 | 0 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 191 |
| Maximum value of voltage frequency, Hz | Frequency Max | 50 | 65 | 51 | 192 | |
| Tripping delay for maximum voltage frequency, s | FreqMax delay | 1 | 300 | 10 | 193 | |
| Permit for protection operation for maximum voltage frequency | FreqMax prot | 0 | 2 | 0 | 0 – “Off” – protection is off; 1 – “OnnAR” – protection is on, ARS after tripping is disabled; 2 – “On AR” – protection is on, ARS is enabled | 194 |
Motor Control and ARS
Section titled “Motor Control and ARS”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| ARS time after protection operation at minimum current, s | AR time Imin | 1 | 900 | 600 | 195 | |
| ARS time, s | AR time | 1 | 900 | 5 | 196 | |
| Disabled ARS for all faults (except voltage faults) | AR | 0 | 1 | 1 | 0 – “Off” – ARS is disabled; 1 – “On” – ARS is enabled. AR parameter value covers all types of faults except voltage faults. To disable AR in case of voltage fault use “Umin protec”, “Umax protec”, “Uimbal protec” | 197 |
| Permit for motor operation after UBZ-305M energizing | Start>Power | 0 | 2 | 1 | 0 – “StOff” – motor starting manually on UBZ-305M front panel; 1 – “St>AR” – motor starting after ARS time; 2 – “St>2s” – motor start after 2s. | 198 |
| Motor control on UBZ-305M front panel | MotorOp UBZ | 0 | 3 | 0 | 0 – “Off” - it is disabled; 1 – “Start” – motor start is enabled; 2 – “Stop” – motor emergency shutdown is enabled; 3 – “St<>” – motor start-up and shutdown is enabled. See section 2.9 | 199 |
| Motor remote start and shutdown via USB/RS485 interface | MotorOp RS-2/5 | 0 | 2 | 0 | 0 – “Off” – remote control is disabled; 1 – “OnSta” – remote control is enabled; motor start after UBZ-305M energizing is enabled after ARS time; 2 – “OffSt” – remote control is enabled, motor start after UBZ-305M energizing is disabled until the command for remote energizing | 200 |
Temperature Control
Section titled “Temperature Control”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Permit for temperature control and type of temperature transmitter 1 | Temp S1 Type | 0 | 2 | 0 | 0 – “Off” – disabled; 1 – “R>1.7” – motor built-in type (protection enabled if transmitter resistance is above 1.7 Ω); 2 – “PTC” – PTC (1kΩ at 25°С) | 201 |
| Motor trip temperature | Temp S1 Off M | 0 | 100 | 80 | 202 | |
| Temperature correction of the first transmitter | Temp S1 Corr | -9 | 9 | 0 | 203 | |
| Permit for temperature control and type of temperature transmitter 2 | Temp S2 Type | 0 | 3 | 0 | 0 – “Off” – disabled; 1 – “Pt100” – Pt100 type; 2 – “Ni100” – Ni100 type; 3 – “Ni120” – Ni120 type. | 204 |
| Motor trip temperature | Temp S2 Off M | 0 | 220 | 180 | 205 | |
| Warning temperature | Temp S2 Alarm | 0 | 220 | 170 | 206 | |
| Temperature correction of the second transmitter | Temp S2 Corr | -9 | 9 | 0 | 207 | |
| ARS after tripping | Temp AR | 0 | 1 | 1 | 0 – “Off” – ARS is disabled; 1 – “On” – ARS is enabled | 208 |
| Temperature transmitters fault reaction | Temp Sens Fault | 0 | 1 | 0 | 0 – “AonM” – warning and continuation of operation; 1 – “AoffM” – warning and motor stop | 209 |
Motor Insulation Resistance
Section titled “Motor Insulation Resistance”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Protection for the motor minimum insulation resistance | Insulation Mr | 0 | 4 | 1 | 0 – “Off” – disabled; 1 – “5 AR” – motor not enabled when insulation <500 kΩ, ARS enabled; 2 – “10 AR” – motor not enabled when insulation <1000 kΩ, ARS enabled; 3 – “5 nAR” – motor not enabled when insulation <500 kΩ, ARS disabled; 4 – “10nAR” – motor not enabled when insulation <1000 kΩ, ARS disabled | 210 |
Miscellaneous
Section titled “Miscellaneous”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Activating the mode of minimum number of settings | Minimal set | 0 | 1 | 1 | 0 – “Off” – mode disabled; 1 – “On” – mode enabled. Mode change possible only in advanced user mode | 211 |
| Indications on UBZ-305M display before starting the motor | Indicat <Start | 0 | 1 | 0 | 0 – “LineU” – line voltage: “Line U1”, “Line U2”, “Line U3”; 1 – “InsFr” – motor running time, insulation resistance, mains frequency | 212 |
| Parameter display mode | Indicat mode | 0 | 1 | 0 | 0 – “Conti” – parameter value displayed continuously; 1 – “>15s” – parameter value displayed for 15 s | 213 |
| Functional relay operating mode | Relay F mode | 0 | 2 | 0 | 0 – “Alarm” – relay used as alarm relay; 1 – “Timer” – relay used as time relay; 2 – “St->D” – relay used for motor star–delta switching | 214 |
| Timer value, s | Relay F time | 0 | 300 | 30 | See “Relay F mode” parameter | 215 |
| Star-delta mode switching time, s | Delay RP RF | 0.1 | 2 | 0.4 | Time between load relay disabling and functional relay enabling in star-delta mode | 216 |
| Total time of the unit operation, day | Time UBZ | 0 | 999 | 0 | When transmitting by USB/RS-485 interface the operating time is transmitted in hours | 217 |
| Motor operating time, day | Time motor | 0 | 999 | 0 | When transmitting by USB/RS-485 interface the operating time is transmitted in hours | 218 |
| Access code of user | Users code | 0 | 9 | 0 | 0 – keyboard is unblocked; 1-9 – user password | 219 |
| Access code of advanced user | Password | 000 | 999 | 123 | 000 – access to advanced user level is permitted; 000-999 – advanced user password | 220 |
| Factory settings reactivating | Default Factor | 0 | 1 | 0 | 0 – “Off”; 1 – “On”. After “On” and settings setup mode quit, factory settings will be reactivated (except advanced user access code) | 221 |
Serial Interface Parameters (RS-485/USB)
Section titled “Serial Interface Parameters (RS-485/USB)”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| UBZ-305M communication address | Address UBZ | 1 | 247 | 1 | 222 | |
| Transfer rate² | Data speed | 0 | 1 | 0 | 0 – “9.6 k” – 9600 baud; 1 – “19.2k” – 19200 baud. | 223 |
| Converter reaction to loss of connection | Loss connect | 0 | 3 | 0 | 0 – “non” – continuation without warning; 1 – “Alarm” – warning and continuation of operation; 2 – “StpAR” – warning and motor stop with ARS permit after restoring connection; 3 – “StpnA” – warning and motor stop with ARS disabled after restoring connection | 224 |
| Detection of response overtime, s | Overexceeding | 0 | 120 | 0 | 0 – disabled | 225 |
| Permit of UBZ-305M communication via serial link | Communication | 0 | 2 | 0 | 0 – “Off” – communication is disabled; 1 – “USB” – communication via USB; 2 – “RS485” – communication via RS-485 | 226 |
| Type of communication protocol² | ASCII-RTU | 0 | 1 | 1 | 0 – “ASCII”; 1 – “RTU” – MODBUS modes | 227 |
| Parity check² | Even parity | 0 | 1 | 0 | 0 – “Off” – parity check disabled; 1 – “On” – parity check enabled | 228 |
| Number of stop bits² | Stop bit | 1 | 2 | 2 | 229 | |
| Unit version | Version | 9 | Parameter value depends on software version | 230 | ||
| Indicator illumination¹ | Indicator L | 0 | 2 | 1 | 0 – “Off” – illumination is off; 1 – “On15s” – illumination on for 15 s after pressing any buttons; 2 – “On” – illumination on continuously | 231 |
| Clock correction, s | Correct Time | -10 | 10 | 0 | Correction of the real time clock. Compensation of time for the day | 232 |
Control via Analog Input 0-20 mA
Section titled “Control via Analog Input 0-20 mA”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Upper threshold, mA | Input I UP | 0 | 20 | 10 | 233 | |
| Lower threshold, mA | Input I DOWN | 0 | 20 | 1 | 234 | |
| Control algorithm | Input I ALG | 0 | 2 | 0 | 0 – “Off” – control is off; 1 – “OffUP” – motor off when current higher than upper threshold, on when lower than lower threshold; 2 – “OnUP” – motor on when current higher than upper threshold, off when lower than lower threshold | 235 |
| Entry in faults logbook | Input I log | 0 | 1 | 0 | 0 – “OffWr” – motor cutoff is the fault but not recorded in logbook; 1 – “OnWr” – motor cutoff is the fault and is recorded in logbook | 236 |
Control via Analog Input 0-10 V
Section titled “Control via Analog Input 0-10 V”| Settings and readings | Parameter on LCD | Min. value | Max. value | Factory setting | Message on LCD, actions | Address |
|---|---|---|---|---|---|---|
| Upper threshold, V | Input U UP | 0 | 10 | 5 | 237 | |
| Lower threshold, V | Input U DOWN | 0 | 10 | 1 | 238 | |
| Control algorithm | Input U ALG | 0 | 2 | 0 | 0 – “Off” – control is off; 1 – “OffUP” – motor off when voltage higher than upper threshold, on when lower than lower threshold; 2 – “OnUP” – motor on when voltage higher than upper threshold, off when lower than lower threshold | 239 |
| Entry in faults logbook | Input U log | 0 | 1 | 0 | 0 – “OffWr” – motor cutoff is the fault but not recorded in logbook; 1 – “OnWr” – motor cutoff is the fault and is recorded in logbook | 240 |
| Serviceability check of external magnetic starter (MS) | Cont Cont | 0 | 1 | 1 | 0 – “Off” – check disabled; 1 – “On” – check enabled | 241 |
| Energy meters reset | Energy RESET | 0 | 1 | 0 | 0 – “Off”; 1 – “On” – reset | 242 |
Notes:
- Indicator light turns off if the line supply voltage is lower than 250 V.
- Parameter change will happen after turning off and repeated energizing or fulfillment of “UBZ RESTART” command
3.4 Protection Functions
Section titled “3.4 Protection Functions”3.4.1 Protection Types
Section titled “3.4.1 Protection Types”UBZ-305M performs the following protection types for electric motors:
- over-current protection in phases
- ground fault protection (for zero-sequence current)
- for negative-sequence current
- for exceeding negative-sequence current factor to negative-sequence voltage factor
- for thermal overload
- undercurrent protection in phases
- delayed starting (rotor blocking)
- overheating of windings
- for minimum line voltage
- for maximum line voltage
- for line voltage imbalance (negative sequence voltage protection)
- for improper phase sequence
- for decreasing of mains frequency lower than setting
- for increasing of mains frequency higher than setting
- for minimum insulation resistance of the motor winding
- for the motor phase loss (protection is operated when the motor current is disabled in one (two) phase)
3.4.2 Maximum Phase Current Protection
Section titled “3.4.2 Maximum Phase Current Protection”Maximum current protection on phase is three phase. It is enabled when one, two or three current values reach the actuation set-point.
The protection has time delay. The time delay can be definite (constant) or dependent (inverse-definite - SIT; very inverse-definite - VIT or LTI; extremely inverse-definite - EIT; ultra inverse-definite - UIT, time delay of RI type) - curves are shown in Appendix A.

In case of the protection with definite time delay the motor is off when the current of one phase is more than specified for the time T (“Imax delay” parameter).
Is = “Imax coef” (tripping ratio) × “Rated Inom” (motor rated current), and T is the delay time of the protection operation (“Imax delay”).
Example: When “Imax coef” = 4.0, “Rated Inom” = 10, “Imax delay” = 10.0, the motor will switch off in 10 seconds after one of the phase currents exceeds 40 amp.
Figure 3.1 – Principle of protection with definite time delay
Protection with dependent time delay corresponds to the standards IEC 60255-3 and BS 142.

In corresponds to the set-point “Rated Inom” (motor rated current); T (“Imax delay” parameter is time constant of the protection operation) corresponds to time delay of tripping for 10×In. For very large currents the protection has a feature with definite time delay.
Figure 3.2 – Principle of protection with dependent time delay
Appendix A provides curves for the time constant of the protection to equal 1 second (“Imax delay” parameter). When setting the different value of the time constant, the response time of the protection is changed proportional to the time constant (for example, when “Imax delay” = 10 seconds, operating time of protection at the same ratio of currents will increase 10 times).
3.4.3 Ground Fault Protection
Section titled “3.4.3 Ground Fault Protection”- It is enabled when ground-fault current reaches the tripping threshold (“I earth tresh” parameter)
- The motor switches off if the ground-fault current is more than specified for the time T (“I earth delay” parameter)
3.4.4 Negative-sequence Current Protection (Imbalance)
Section titled “3.4.4 Negative-sequence Current Protection (Imbalance)”Negative-sequence current protection (imbalance) is enabled when a component of the negative sequence is more than the set-point (“I2 rev tresh” parameter) and stops the motor when time of this excess is more than specified value (“I2 rev delay” parameter).
If the analysis of tripping cause is enabled (“A-s I2 prot”=“On”), then in case of protection tripping due to exceeding of negative sequence current not because of line voltages imbalance (in this case the motor problems are assumed), ARS after tripping will not occur (regardless of the value of “I2 rev protec” parameter).
The coefficient of negative voltage (current) sequence is characteristic of unbalance of three-phase voltage (current). Approximately the coefficient of negative voltage sequence is determined by the formula:
Where:
- — RMS value of negative voltage sequence of fundamental frequency of three-phase voltage system in i-observation, V
- — RMS value of positive voltage sequence of fundamental frequency in i-observation, V
is calculated by the approximate formula:
where , are maximum and minimum RMS values of the three phase-to-phase voltage of the fundamental frequency in i-observation, V.
The coefficient of negative current sequence is calculated similarly.
If currents imbalance is caused not by voltage imbalance, then motor fault is determined. To determine the cause of currents imbalance it is necessary to calculate the ratio of the coefficient of negative current sequence to the coefficient of negative voltage sequence (). And if the ratio is more than the value of “A-s I2 coef” parameter, then UBZ-305M considers that the motor has malfunction.
3.4.5 Minimum Phase Current Protection
Section titled “3.4.5 Minimum Phase Current Protection”- It is enabled when the currents of all three phases drops lower than the set-point (“Imin tresh” parameter) and stops the motor when this drop time is more than the specified one (“Imin delay” parameter)
- It is not active when the load current is less than 10% In (when decrease of the current is due to motor shutdown, not due to decrease of its load)
- It has its own definite time delay of ARS (“AR time Imin” parameter)
3.4.6 Delayed Start and Rotor Blocking
Section titled “3.4.6 Delayed Start and Rotor Blocking”The principle of delayed start protection and rotor inter-blocking is given in Figure 3.3.

Delayed start
During start-up the protection is enabled when all phase currents are more than the set-point Is (“Start I Coef” parameter) during the period of time more than the ST time delay (“Start delay I” parameter).
Rotor blocking
After motor start performing (reducing the starting current lower than 1.2 of rated one) UBZ-305M switches to control of possible blocking of the rotor. The protection system operates when all the phase currents are more than set-points during a period of time greater than LT time delay (“Block I delay” parameter).
Figure 3.3 – Delayed start and rotor blocking
3.4.7 Thermal Overload Protection
Section titled “3.4.7 Thermal Overload Protection”Thermal overload protection is made on the basis of the equation solution of motor thermal balance under the following assumptions:
- before the first start the motor was cold
- during the motor operation, heat generates that is proportional to the square of the current
- after motor turning off it is cooled down exponentially
For protection, you should enter the response time in case of double overload T2 (the parameter of “Thermal delay”).
For the standard recommended T2 value (60 s at 2 time overload) the following current-time characteristic applies:
Table 3.7 – Current-time characteristic
| I/Inom | 1.1 | 1.2 | 1.4 | 1.7 | 2 | 2.7 | 3 | 4 | 5 | 6 | 7 | 8 | 10 | 15 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| T (sec) | 365 | 247 | 148 | 88.6 | 60 | 36.4 | 24.6 | 13.5 | 8.5 | 5.9 | 4.3 | 3.3 | 2.1 | 0.9 |
For rotating machines, cooling is more efficient during operation than during the stop of the motor, so enter the parameter “Thermal C stop” - the constant increase rate of cooling when the motor is stopped.
After the load relay disabling owing to thermal overload with ARS permitted, the relay will be enabled again after the time more than the maximum of the two values:
- time of thermal hysteresis (motor should cool down to 33% of the accumulated heat)
- time of ARS
Choosing different ARS time periods considering thermal hysteresis, one can reduce the number of starts per time unit because in the intermittent mode of operation UBZ-305M remembers the amount of heat released during the motor start.

- I/Iн – current ratio relative to rated one
- Т/Т2 – the actual response time relative to T2 (response time when double overload)
Figure 3.4 – Current-time characteristic
3.4.8 Windings Overheating Protection
Section titled “3.4.8 Windings Overheating Protection”First input protection:
- When working with motor built-in temperature transmitters (parameter “Temp S1 Type”=“R>1.7”) protection is enabled when the transmitter resistance will be more than 1700 Ω. Set-point “Temp S1 Off M” is not used: short-circuit and breakout of the transmitter is not controlled
- When working with transmitters of PTC type (1kΩ at 25°C) (“Temp S1 Type” = PTC parameter), protection is enabled and stops the motor when the monitored temperature is more than the set-point (“Temp S1 Off M” parameter)
When working with PTC type transmitters, protection defines the cases of breakout and short circuit of the transmitter:
- breakout at temperature higher than 100°C
- short circuit at temperature less than minus 45°C
Second input protection:
- It is enabled when the controlled temperature is higher than set-point
- It has two independent set-points: the alarm set-point (“Temp S2 Alarm” parameter) and the set-point for the motor is off (“Temp S2 Off M” parameter)
Protection determines the cases of breakout and short circuit of the temperature transmitters:
- breakout at temperature of more than 220°C
- short circuit at temperature of less than minus 45°C
On the second input the protection is operated with temperature transmitters of Pt100 type (platinum type for 100 Ω at 0°C) or Ni100 (Ni120) (Nickel type for 100 Ω (120 Ω) at 0°C) in accordance with the standards of IEC 60751 and DIN 43760.
3.4.9 Voltage Protection
Section titled “3.4.9 Voltage Protection”In UBZ-305M voltage protection before enabling the load it is necessary to check the corresponding set-points and depending on their value, the load relay enabling will be permitted or disabled; when the motor is on, the voltage control is fulfilled, but the decision relative to disabling is made according to currents.
The voltage protections are the following:
- At minimum line voltage - enabled if at least one of the line voltages is less than the set-point (“Umin tresh” parameter) within the time specified by “Umin delay” parameter
- At maximum line voltage - enabled if at least one of the line voltages is more than the set-point (“Umax tresh” parameter) within the time specified by “Umax delay” parameter
- During line voltages imbalance - enabled if the difference between effective values of the line voltages is more than the set-point (“Uimbal tresh” parameter) within the time specified by “Uimbal delay” parameter
3.4.10 Phase Sequence Protection
Section titled “3.4.10 Phase Sequence Protection”Phase sequence protection (“Correct phase” parameter) is enabled in case of improper phase sequence; it disables the motor and blocks its further operation.
3.4.11 Network Power Frequency Drop Protection
Section titled “3.4.11 Network Power Frequency Drop Protection”Network power frequency drop protection is enabled if the network power frequency is less than the set-point (“Frequency Min” parameter) within the time specified by “FreqMin delay” parameter.
3.4.12 Network Power Frequency Rise Protection
Section titled “3.4.12 Network Power Frequency Rise Protection”Network power frequency rise protection is enabled if the network power frequency is higher than the set-point (“Frequency Max” parameter) within the time specified by “FreqMax delay” parameter.
3.4.13 Protection for Minimum Resistance of Motor Winding Insulation
Section titled “3.4.13 Protection for Minimum Resistance of Motor Winding Insulation”After UBZ-305M energizing before the output relay will be on, it is necessary to check the insulation level of stator winding relative to the housing. The level of stator winding insulation relative to housing is also checked, when the load relay is on, but the motor currents are less than 10% of rated current (in this case UBZ-305M considers that the motor is off).
When “Insulation Mr” = “5 AR” (“5 nAR”) the load is disabled if the insulation resistance is lower than 500 kΩ ±20 kΩ, and when “Insulation Mr” = “10 AR” (“10 nAR”) if it is less than 1000 kΩ ±50 kΩ. During automatic restarting “AR”, the load will on after restoring the insulation resistance and after ARS time finishing. If “nAR”, ARS will not on.
3.4.14 Protection for Motor Phase Break (Loss)
Section titled “3.4.14 Protection for Motor Phase Break (Loss)”Protection for the motor phase (-s) break (loss) is enabled if one of the motor phase current is more than 10% of the rated one (“Rated Inom” parameter), and any of the remaining phases of the motor is less than 7% of the motor rated current.
3.4.15 Serviceability Check of External Magnetic Starter
Section titled “3.4.15 Serviceability Check of External Magnetic Starter”UBZ-305M detects the motor currents when the load relay is off (if the load relay and functional relay is off in star-delta mode). In this case, UBZ-305M indicates the fault of external MS enabling the motor, until then UBZ-305M is turned off or control of the motor currents is disabled when load relay is off (“Cont Cont” = 0 (“Off”) parameter).
4. UBZ-305M Design
Section titled “4. UBZ-305M Design”UBZ-305M is microprocessor-based digital device that provides a high degree of reliability and accuracy. Operational power is not required. The controlled voltage is simultaneously the power supply voltage.
5. Intended Use
Section titled “5. Intended Use”5.1 Preparation for Operation
Section titled “5.1 Preparation for Operation”5.1.1 Preparation for Connection
Section titled “5.1.1 Preparation for Connection”- Unpack and check the Unit for damage after transportation; in case of such damages detection, contact the supplier or manufacturer
- Check for components (section 2), in case of detection of incomplete Unit, contact the supplier or manufacturer
- Carefully study the Operating Manual (pay special attention to the connection diagram to power the Unit)
- If you have any questions regarding the installation of the Unit, please contact the manufacturer by telephone number indicated at the end of this Operating Manual
5.1.2 Selection of Current Transformers (CT)
Section titled “5.1.2 Selection of Current Transformers (CT)”- Rated output current of CT should be 5 A
- Rated input current of CT (Ict) is selected based on the rated current of the motor (In), the motor starting current, start duration, the time required for ARS (taking into account the characteristics of UBZ-305M inputs designed to connect CT (Table 5.1))
Table 5.1 – Characteristics of UBZ-305M inputs designed to connect CT
| Current of UBZ-305M inputs designed for measurement of CT output currents, A | Ratio of overload relative to rated current (5 A) | Maximum duration of current action, s | Minimum delay before restarting, s |
|---|---|---|---|
| 0 – 12 | 2.4 | continuously | - |
| 12 – 15 | 3 | 60 | 10 |
| 16 – 20 | 4 | 30 | 15 |
| 21 – 25 | 5 | 15 | 30 |
Rated input current of CT should be within the range: In < Ict < 3×In.
It is recommended to use CT with Ict = 2×In.
5.1.3 General
Section titled “5.1.3 General”To ensure the reliability of electrical connections you should use flexible (stranded) wires with insulation for voltage of not less than 450V, the ends of which it is necessary to be striped of insulation for 5±0.5 mm and tightened with bootlaces. Recommended cable cross section for connection is not less than 1 mm².
Wires fastening should exclude mechanical damage, twisting and insulation abrasion of wires.
IT IS NOT ALLOWED TO LEAVE EXPOSED PORTIONS OF WIRE PROTRUDING BEYOND THE REMOVABLE TERMINAL BLOCK.
For reliable contact it is necessary to perform tightening of screws of removable terminal block with the force specified in Table 3.1.
When reducing the tightening torque, the junction point is heated, terminal block may be melted and wire can burn. If you increase the tightening torque, it is possible to have thread failure of terminal block screws or the compression of the connected wires.
5.1.4 UBZ-305M Connection
Section titled “5.1.4 UBZ-305M Connection”5.1.4.1 Connect the current transformers in accordance with Figure 5.1.
5.1.4.2 Pass through a differential current transformer (zero sequence transformer) all three phase wires and connect it to UBZ-305M.
5.1.4.3 To monitor and measure the motor insulation, connect the control terminal of the insulation 25 to one of output contacts of MS. If the motor housing is not grounded, or network with isolated neutral is used, or neutral wire is not connected to UBZ-305M terminal, it is necessary to connect electrically the motor housing to the terminal 26 of UBZ-305M.
5.1.4.4 Connect the motor to UBZ-305M in accordance with Figure 5.1. When using the motor with the switching over the windings during star-delta starting-up, perform the connection in accordance with Appendix B.
5.1.4.5 In case of MODBUS usage, connect the communication lines RS-485 to terminals 33 (GND), 34 (line B RS-485), 35 (line A RS-485) of UBZ-305M. Set the parameter of “Communication” = “RS485”.

- A – UBZ-305M
- F1-F3 – Fusible element for 1 A (or its equivalent)
- K – Magnetic starter (MS)
- R1 – Temperature transmitter (for example: PT100)
- R2 – Temperature transmitter (for example: PTC1000, EKS111 made by DANFOSS)
- Q – Circuit breaker
- QF – Circuit breaker at a maximum current of 6.3 A
- T1-T3 – Current transformer (output 5 A)
- T4 – Differential transformer
Figure 5.1 – UBZ-305M Connection Diagram
5.1.4.6 Energize UBZ-305M
The enabling sequence for the load relay after energizing is determined by the values of the parameters “AR time” and “Start>Power” (see section 5.3.1.1).
5.1.4.7 In the course of first starting in accordance with factory settings UBZ-305M is in the mode of MNS in which it is possible to set the following parameters:
- CT rated current (parameter of “CT nom i”)
- motor rated current (parameter of “Rated Inom”)
For normal operation of UBZ-305M it is enough to set these parameters according to used CT and the motor.
5.1.4.8 To operate the device together with PC as a control or monitoring device using the program “Control Panel UBZ-304/305”, it is necessary to:
- Connect your PC to the Internet
- Download on PC the file “Setupcplubz304_305(_X.X).exe” (X.X is the version number of the software) from the site of NOVATEK-ELECTRO (https://novatek-electro.com/en/software/control-panel-of-ubz-304305.html)
- Install on PC “Control Panel UBZ-304/305” by running the file “Setup_cplubz304_305”
5.1.4.9 For the device to work with a PC via the USB interface, you must:
- Connect your PC to the Internet
- Upload the “USB-serial-Novatek.rar” file from the NOVATEK-ELECTRO website to your PC
- Unpack the archive and install the driver on the PC by running the file “setup.exe”
- Connect the “USB” connector on the device panel to the USB connector of PC using the “USB type A-microUSB type B” cable
- Select “COM port” in the “Communication settings” section (“Settings” menu of the program “Control Panel UBZ-304/305”) the number of the appeared additional COM port and make sure that the other communication settings correspond to the UBZ-305M communication settings
- Set the “Communication” parameter = “USB” in UBZ-305M
5.1.4.10 Disable power of UBZ-305M.
5.1.4.11 Connect the magnetic starter (hereinafter referred as MS) of the motor in accordance with Figure 5.1.
5.2 UBZ-305M Control
Section titled “5.2 UBZ-305M Control”5.2.1 Modes of UBZ-305M Control and Status
Section titled “5.2.1 Modes of UBZ-305M Control and Status”UBZ-305M has five control modes:
- Keyboard blocking
- MNS
- User level
- Advanced user level
- Remote control
All the modes of control have possibility to switch UBZ-305M in the state:
- Viewing the measured and calculated parameters (Table 3.5)
- Viewing the faults logbook (section 5.6)
5.2.2 Measured and Calculated Parameters View State
Section titled “5.2.2 Measured and Calculated Parameters View State”Measured and calculated parameters view state is the principal state. From all other modes UBZ-305M returns to this mode automatically (if after 30 s, no button is pressed).
In this mode the first three lines of the indicator displays a group of three functionally close settings (when adding the values of temperature transmitters or analog inputs – a group of two parameters) (Figure 5.2).
The information displayed in the fourth line of the indicator depends on the state of UBZ-305M.
If the load relay is enabled, then the fourth line of the display shows the current time (Figure 5.2).

The display shows:
- In line 1 – current in phase A – 345 A
- In line 2 – current in phase B – 350 A
- In line 3 – current in phase C – 342 A
- In line 4 – current time
Figure 5.2 – UBZ-305M Indicator in view mode of measured and calculated parameters (load relay is on)
If the load relay is off, then the fourth line of the indicator can display the following:
- “AR=NOT Ir=0 15:30:17” in case if the motor start is impossible as the motor rated current is not set (parameter of “Rated Inom” =0)
- “AR=NOT 15:30:17” in case if the fault occurred after which ARS is disabled
- “AR=350 15:30:17” in case if the fault occurred and ARS is possible (ARS time account is on – 350 s left to ARS)
In the second and third variant, information of the fourth line of the indicator is consistently changing – in addition to reports about the possibility of starting the motor; it displays the total number of faults and type of fault on the display (Figure 5.3).

The display shows:
- In line 1 – line voltage U1 – 345 V
- In line 2 – line voltage U2 – 312 V
- In line 3 – line voltage U3 – 210 V
- In line 4 – “Imax” – type of fault (over-current protection); “Er 3:8” – the indicator displays the third fault; total number of existing types of faults is 8
Figure 5.3 – UBZ-305M Indicator in view mode of measured and calculated parameters (in fault conditions)
5.2.3 Mode of Keyboard Blocking
Section titled “5.2.3 Mode of Keyboard Blocking”When the keyboard is blocked you cannot view and reinstall the programmable parameters.
When the keyboard is blocked, pressing the “SETUP” button leads to the appearance on the indicator the message “blocked buttons” (Figure 5.4).

Figure 5.4 – Indicator when the keyboard is blocked
To unblock the keyboard, it is necessary to press again the “SETUP” button. The led turns on “SETUP”, and the indicator displays the inscription “USERS PASSWORD” and “<0>”. With the help of UP and DOWN buttons you can dial the digit of user password from 1 to 9 and can press the button “WR/SEL”. If the password is correct, the keyboard is unblocked. If after unblocking the keyboard no button is pressed within 15 s and setting of blocking has not been disabled by the user, the keyboard is blocked again.
5.2.4 Mode of Minimum Number of Settings (MNS)
Section titled “5.2.4 Mode of Minimum Number of Settings (MNS)”Mode of MNS is designed to facilitate the work of the service personnel with UBZ-305M.
In case of initial factory settings UBZ-305M is in the mode of MNS.
When UBZ-305M is operated in the mode of MNS the green led “MMSP” is on.
UBZ-305M operation in MNS mode differs from UBZ-305M operation in the mode of user level that the parameters not included in the list of MNS are set to factory defaults, and when you log in the user menu they are not visible.
Operation with parameters those are included in the list of MNS is the same as with the settings in the mode of user level (section 5.3.5).
When the mode of MNS is disabled (setting of parameter “Minimal set” is in “Off” position), the led “MMSP” goes out and UBZ-305M switches to the user level. At the user level you can change all the settings (included and not included in the list of MNS), if the change is not disabled by the advanced user.
UBZ-305M will transfer to the MNS mode after reset to factory settings (section 5.2.7).
5.2.5 Mode of User Level
Section titled “5.2.5 Mode of User Level”When UBZ-305M unit is in the user-level mode, led “MMSP” is off.
To view and change the parameters of user level you should press the “SETUP” button, the led “SETUP” is on and the indicator displays the user menu (Figure 5.5).

Figure 5.5 – User Menu
Using DOWN and UP buttons select the desired parameter (in Figure 5.5, “CT nom i” parameter is selected; it is the rated current of the CT) and press the “SETUP” button (Figure 5.6).

Figure 5.6 – Screen of changing the setting in the user mode
If the fourth line of the indicator is marked by “ADV” (Figure 5.6), the change of the parameter value in the user mode is disabled and in this case it can only be changed in the mode of Advanced user level.
If the parameter is not in the list of MNS (the fourth line of the indicator has the inscription “OFF MMSP”), then to change the value of the parameter it is necessary preliminary to include it in the list of MNS. To do this:
- using DOWN and UP buttons select the parameter
- press “SETUP” button
- press simultaneously DOWN and UP buttons (on the display instead of the inscription “OFF MMSP” the inscription “MMSP” should remain)
The value of the parameter in the user mode can be changed if the fourth line of the indicator has only the inscription “MMSP”. To do this:
- using buttons DOWN or UP select the desired parameter value
- using the button “WR/SEL”, record the value of the parameter, and to go back to menu without recording, press the “SETUP” button
If no button is pressed within 30 seconds, UBZ-305M switches to the state of the viewing the measured and the calculated parameters.
To exit to menu before 30 seconds you need to press button “WR/SEL”.
5.2.6 Mode of Advanced User Level
Section titled “5.2.6 Mode of Advanced User Level”Access to the advanced user level
Press the “SETUP” button for 5 seconds, release the button.
If the level is password protected, the led “SETUP” is on and the display shows the PASSWORD inscription and “000” will flash (Figure 5.7).

Figure 5.7 – Advanced user password
Using UP and DOWN buttons sequentially, enter the three-digit password of advanced user, from 1 to 9 and separate dialing with pressing the button “WR/SEL”. If the password is wrong, then LCD will display “ERROR” and after 15 seconds UBZ-305M will return to the view state of the parameters, otherwise UBZ will go to the advanced user level (Figure 5.8).

Figure 5.8 – Advanced user level
The procedure for changing the settings on the advanced user level is the same as user-level (section 5.2.5), but the parameter recording does not depend on the inscription “ADV” presence in the fourth line of the indicator. However, to change the value of the parameter, the parameter should be included in the list of MNS.
At the advanced user level the availability of any parameter at the user level can be disabled or enabled. To do this:
- using DOWN and UP buttons, select the parameter (Figure 5.8)
- enter the menu where setting is changed by pressing “SETUP” button
- press both buttons “SETUP” and DOWN
In case of restricting access to change the parameter at the user level in the fourth line of the indicator the inscription “ADV” will display.
5.2.7 Factory Settings
Section titled “5.2.7 Factory Settings”Factory settings are possible in two ways.
First method: set the parameter “Default Factor” to “On”. After exiting from the mode for setting the factory settings will be restored.
This method does not recover the following settings:
- access code of advanced user (“Password”)
- current time and date
- clock correction (“Correct Time”)
- the unit operating time (“Time UBZ-305M”)
- operating time of the motor (“Time motor”)
Second method: when UBZ-305M energizing, hold pressed for two seconds the buttons “SETUP” and “WR/SEL”. Factory settings are restored (advanced user password - 123).
This method does not recover the following settings:
- the unit operating time (“Time UBZ-305M”)
- operating time of the motor (“Time motor”)
- clock correction (“Correct Time”)
After you complete the installation of factory parameters, UBZ-305M will start operation in the mode of MNS, the list of which the settings are included:
- CT output current, “CT out i”
- CT rated current, “CT nom i”
- motor rated current, “Rated Inom”
5.2.8 Real Time Setting
Section titled “5.2.8 Real Time Setting”To set the real time:
- pressing “SETUP” button, enter the parameters setting mode
- using UP and DOWN buttons, select parameter “Real Time”
- press the button “SETUP” (Figure 5.9)

Figure 5.9 – View of the display when setting the time
- using UP and DOWN buttons, select the desired date and press the button “WR/SEL”
- repeat step 4 to set the month, year, hour and minute
When recording minutes (at the moment of pressing the button “WR/SEL”), the number of seconds will be automatically set to zero.
If you move to the next parameter without changes, instead of the button “WR/SEL”, press the button “SETUP”.
If no button is pressed for 15 seconds, UBZ-305M will automatically switch to the parameter view mode.
5.2.9 UBZ-305M Faults Reset on Front Panel
Section titled “5.2.9 UBZ-305M Faults Reset on Front Panel”Fault reset is performed when the motor is off. To reset the faults on the front panel, press simultaneously the buttons “SETUP” and DOWN, in this case:
- faults are reset regardless of whether ARS is disabled or enabled (besides the current faults and faults by the presence of motor currents when load relay is off)
- counting of ARS is off
- in the absence of the current troubles the motor is off
5.2.10 Energy Meters Reset
Section titled “5.2.10 Energy Meters Reset”Reset of energy meters (total, active and reactive) is performed when setting the parameter “Energy RESET” to “On” (setting to “1” when using USB/RS-485 interface). After reset of energy meters, the parameter “Energy RESET” will automatically switch to “Off” (“0” – when reading the parameter via USB/RS-485 interface).
5.3 UBZ-305M Operation
Section titled “5.3 UBZ-305M Operation”In describing the operation of UBZ-305M it is assumed that this protection is enabled and all the required sensors are connected.
5.3.1 UBZ-305M Operation Before Load Relay On
Section titled “5.3.1 UBZ-305M Operation Before Load Relay On”5.3.1.1 UBZ-305M Operation After Energizing (First Start-up)
Section titled “5.3.1.1 UBZ-305M Operation After Energizing (First Start-up)”After energizing the indicator displays the device name, the version number of software, the name of the manufacturer and the operation performed (Figure 5.10).

Figure 5.10 – UBZ-305M indicator view after energizing
After 1-2 seconds the indicator will display the values of the measured parameters. What parameters will be displayed on the indicator it depends on the value of the parameter “Indicat <Start”:
- line voltages at “Indicat <Start”=“LineU”
- the motor operating time, the insulation resistance of the motor and mains frequency at “Indicat <Start”= “InsFr”
Before the load relay enabling UBZ-305M checks the following:
- the level of stator winding insulation relative to the motor housing (when insulation resistance is less than 500 ± 20 kΩ at “Insulation Mr” = “5” (1000 ± 50 kΩ at “Insulation Mr” = “10”) the load is not enabled)
- the quality of the mains voltage: full phase, symmetry, the current line voltage value
- correct phase sequence, the lack of their “coincidence”
If any of disabling factors, the load relay is not activated, and the display of mnemonics shows the corresponding message about the fault (Table 5.13) and the led “FAULT” lights up.
In the absence of disabling factors, enabling the load relay is determined by the value of parameter “Start>Power” (UBZ-305M operation after energizing):
- when “Start>Power” = “StOff”, the load relay will not be enabled. To enable the load relay in this case, you should simultaneously press UP and DOWN buttons.
- when “Start>Power” = “St>AR” the load relay will be enabled after ARS time.
- when “Start>Power” = “St>2s” the load relay will be enabled within 2 seconds after energizing.
Simultaneously with the load relay enabling the green led “Power relay” lights up.
After you activate the relay and up to the moment of the motor starting (motor start is determined by the excess of the load current of 120% level of rated current), control and taking action on voltage quality is maintained. If within no-current pause the disabling factors are appeared, the load relay is deactivated.
UBZ-305M operation when enabled remote control of the motor via USB/RS-485 interface (parameter “MotorOp RS-2/5”) is considered in section 5.4.9.
5.3.1.2 UBZ-305M Operation After Shutdown Owing to the Fault
Section titled “5.3.1.2 UBZ-305M Operation After Shutdown Owing to the Fault”UBZ-305M operation in this case is similar to the work when first starting, but enabling the load relay does not depend on the value of the parameter “Start>Power”.
If after the fault ARS is disabled (“AR”=“Off”), then with disabled motor start on the front panel (it is determined by the value of the parameter “MotorOp UBZ-305M”) the automatic enabling the motor is impossible up to UBZ-305M turning off. The action of the parameter “AR” value is applied to all types of faults except voltage faults. To disable ARS in case of voltage faults you should use the parameters “Umax protec”, “Umin protec”, “Uimbal protec”.
5.3.2 UBZ-305M Operation After Load Relay Enabling and Motor Is On
Section titled “5.3.2 UBZ-305M Operation After Load Relay Enabling and Motor Is On”UBZ-305M provides monitoring for voltage and currents. The load relay is disabled when any protection tripping from Table 5.13 with the exception of:
- voltage protection
- overcurrent protection with “Imax<>T” =“Ind” (in this case, the warning is there, but the load relay is not disabled)
The indicator can display phase currents of motor or group of three (two) parameters selected by the user (Table 3.5). The group of parameters selected by the user can be displayed constantly (“Indicat mode”=” Conti”) or for 15 s, and then indication of motor currents returns (“Indicat mode ” = “>15s”).
5.3.3 Functional Relay Operation
Section titled “5.3.3 Functional Relay Operation”The functions performed by the functional relay are determined by the parameter “Relay F mode”.
When “Relay F mode” = “Alarm”, the relay is used as alarm relay (LEDs ”⚠” and “TR” do not on). The relay contacts are closed when there is any fault specified in Table 5.13.
When “Relay F mode” = “Timer”, the relay is used as time relay (LED “TR” is on): it turns on after the time set by the parameter “Relay F time”, after the load relay enabling.
When “Relay F mode” = “St->D”, the relay is used to switch the motor windings from star to delta (LED ”⚠” is on). In this mode the load relay is activated the same way as in the mode “Alarm”, but after the time set by parameter “Relay F time” it is disabled. After the time set by the parameter “Delay RP RF”, after the load relay is off, the functional relay is activated.
5.4 Operation of UBZ-305M Together with Computer
Section titled “5.4 Operation of UBZ-305M Together with Computer”5.4.1 Communication Protocol and Interface
Section titled “5.4.1 Communication Protocol and Interface”The communication between UBZ-305M and computer can be via USB or RS-485 interface (parameter “Communication”).
For communication MODBUS Protocol is used in RTU mode or MODBUS in ASCII mode (parameter “ASCII-RTU”).
In ASCII mode 8-bit data is the combination of two ASCII characters (Table 5.2). For example, 1–data byte: 64 Hex, in ASCII consists of two characters ‘6’ (36 Hex) and ‘4’ (34 Hex).
Table 5.2 – ASCII characters
| Character | ’0' | '1' | '2' | '3' | '4' | '5' | '6' | '7’ |
|---|---|---|---|---|---|---|---|---|
| ASCII code | 30 Hex | 31 Hex | 32 Hex | 33 Hex | 34 Hex | 35 Hex | 36 Hex | 37 Hex |
| Character | ’8' | '9' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F’ |
|---|---|---|---|---|---|---|---|---|
| ASCII code | 38 Hex | 39 Hex | 41 Hex | 42 Hex | 43 Hex | 44 Hex | 45 Hex | 46 Hex |
In RTU mode 8-bit data is the combination of 4-bit hexadecimal digits. For example, 64 Hex.
During data exchange via RS-485 or USB the blue LED “RS-485” is on.
Each UBZ-305M has the individual communication address. The computer controls each UBZ-305M recognizing them by their addresses.
5.4.2 Communication Parameters
Section titled “5.4.2 Communication Parameters”- the unit address: 1-247 (parameter “Address UBZ-305M”)
- data transfer rate: 9600 baud, 19200 baud (parameter “Data speed”)
- reaction to loss of connection: the continuation of operation with no warning, the warning and continued operation, the warning and stopping the motor with ARS enabling after restoration of communication, warning and motor stop with ARS disabling (parameter “Loss connect”)
- detection of exceeded time for reply: 1s – 120s (parameter “Overexceeding”)
The format of the transmitted word is the following:
- 8 data bits in RTU mode and 7 data bits in ASCII mode
- parity check (parameter “Even parity”): disabled (“Off”), enabled (“On”); (factory setting is “Off”)
- number of stop bits (parameter “Stop bit”): 1 or 2 (factory setting is 2)
5.4.3 Communication Protocol
Section titled “5.4.3 Communication Protocol”Exchange between PC and UBZ-305M is carried by data packets. Data packet format in RTU mode is shown in Table 5.3 and in ASCII mode – in Table 5.4.
Table 5.3 – Data packet in RTU mode
| Name | Description |
|---|---|
| START | Silence interval – over 4 ms at transmission rate of 9600 baud, or more 2 ms at 19200 baud |
| ADR | UBZ-305M communication address (8 bit) |
| CMD | Command code 8 bit |
| DATA 0…n-1 | Content of data: N*8 bit data (n<=24) |
| CRC CHK low | CRC – Cyclic Redundant Check, 16 bit |
| CRC CHK high | |
| END | Silence interval – over 4 ms at transmission rate of 9600 baud, or more 2 ms at 19200 baud |
Table 5.4 – Data packet in ASCII mode
| Name | Description |
|---|---|
| STX | Start character ’:’ (3A Hex) |
| ADR1, ADR0 | UBZ-305M communication address (8 bit) consisting of two ASCII chars |
| CMD1, CMD0 | Command code 8 bit consisting of two ASCII characters |
| DATA 0…n-1 | Content of data: N*8 bit data (n<=24) consisting of two ASCII chars |
| LRC CHK 1, 0 | LRC Cyclic Redundant Check: 8-bit control total as two ASCII chars |
| END1 | End of characters: END1= 0D Hex – carriage return (CR) |
| END0 | END0 = 0A Hex – line feed (LF) |
5.4.4 Command Codes
Section titled “5.4.4 Command Codes”5.4.4.1 General
Section titled “5.4.4.1 General”The format of data characters depends on command codes. Examples of transmission of commands and data are given for RTU mode. For ASCII mode the command codes are not changed, but the format of the transmission data and control of data is based on the Table 5.4.
5.4.4.2 Command for Reading the Register Group
Section titled “5.4.4.2 Command for Reading the Register Group”Command code – 0x03, reading n-words
For example, reading of continuous 2 words from starting address 2102H in UBZ-305M with communication address 01H in RTU mode (Table 5.5) and in ASCII mode (Table 5.6).
Table 5.5 – Command for reading registers (RTU mode)
| Command message | Response message | ||
|---|---|---|---|
| ADR | 0x01 | ADR | 0x01 |
| CMD | 0x03 | CMD | 0x03 |
| Start address of data | 0x21 | Number of data in bytes | 0x04 |
| 0x02 | |||
| Number of data in words | 0x00 | Content of data at address | 0x17 |
| 0x02 | 0x70 | ||
| CRC CHK low | 0x6F | Content of data at address | 0x00 |
| 0x00 | |||
| CRC CHK high | 0xF7 | CRC CHK low | 0xFE |
| CRC CHK high | 0x5C |
Table 5.6 – Command for reading registers (ASCII mode)
| Command message | Code transferred, HEX | Numbers for LRC, HEX | |
|---|---|---|---|
| STX | ’:‘ | 3A | |
| ADR | ’0’ | 30 | 01 |
| ’1’ | 31 | ||
| CMD | ’0’ | 30 | 03 |
| ’3’ | 33 | ||
| Start address | ’2’ | 32 | 21 |
| ’1’ | 31 | 02 | |
| ’0’ | 30 | ||
| ’2’ | 32 | ||
| Number of words | ’0’ | 30 | 00 |
| ’0’ | 30 | 02 | |
| ’0’ | 30 | ||
| ’2’ | 32 | ||
| LRC CHK 1 | ’D’ | 44 | |
| LRC CHK 0 | ’6’ | 36 | |
| END1 | CR | 0D | |
| END0 | LF | 0A |
5.4.4.3 Command of Register Entries
Section titled “5.4.4.3 Command of Register Entries”Command code – 0x06, record – one word
Data recording is possible at the addresses of programmable parameters (Table 3.6), except the parameters listed in Table 5.7.
The parameter recording is independent of set protection of the advanced user (entry by the communication line has higher priority).
When recording new value of the parameter into the cell protected by MNS, the parameter is automatically removed from this mode.
Table 5.7 – Parameters not available for recording via MODBUS
| Settings and readings | Displaying | Address |
|---|---|---|
| Total time of the unit operation | Time UBZ | 217 |
| Motor operating time, day | Time motor | 218 |
| Access code of user | Users code | 219 |
| Access code of advanced user | Password | 220 |
| Restoration of factory settings | Default Factor | 221 |
| The unit design version | Version | 230 |
Example: recording order is 1000 (0x03E8) to register with address 0x00A0 to UBZ-305M with communication address 01H in RTU mode is shown in Table 5.8.
Table 5.8 – Command for writing register (RTU mode)
| Command message | Response message | ||
|---|---|---|---|
| ADR | 0x01 | ADR | 0x01 |
| CMD | 0x06 | CMD | 0x06 |
| Start address of data | 0x00 | Start address of data | 0x00 |
| 0xA0 | 0xA0 | ||
| Data | 0x03 | Data | 0x03 |
| 0xE8 | 0xE8 | ||
| CRC CHK low | 0x89 | CRC CHK low | 0x89 |
| CRC CHK high | 0x56 | CRC CHK high | 0x56 |
5.4.4.4 Command for Diagnostics
Section titled “5.4.4.4 Command for Diagnostics”Command code 08h – diagnostics
The 08h function provides a number of tests for checking the communication system between PC and UBZ-305M, and UBZ-305M serviceability control.
The function uses the sub-function field to specify the action performed (test).
Sub-function 00h - return of request data
The data transmitted in the data field of the request should be returned in the response data field.
Example of request and response for MODBUS RTU mode:
Request:
| Address | Function | Sub-function HB | Sub-function LB | Data HB | Data LB | CRC LB | CRC HB |
|---|---|---|---|---|---|---|---|
| 01h | 08h | 00h | 00h | A0h | 3Ch | 98h | 1Ah |
Response:
| Address | Function | Sub-function HB | Sub-function LB | Data HB | Data LB | CRC LB | CRC HB |
|---|---|---|---|---|---|---|---|
| 01h | 08h | 00h | 00h | A0h | 3Ch | 98h | 1Ah |
Sub-function 01h – restart of communication options
During fulfillment of the command UBZ-305M performs only change in baud rate. To change totally the communication settings you should run the command “UBZ RESTART” (“RESTART”).
Example of request for MODBUS RTU mode:
| Address | Function | Sub-function HB | Sub-function LB | Data HB | Data LB | CRC LB | CRC HB |
|---|---|---|---|---|---|---|---|
| 01h | 08h | 00h | 01h | 00h | 00h | B1h | CBh |
Response is not returned.
5.4.5 Control of Correct Transmission of Data Packet
Section titled “5.4.5 Control of Correct Transmission of Data Packet”5.4.5.1 Control in RTU Mode
Section titled “5.4.5.1 Control in RTU Mode”To check the correctness of data transmission in RTU mode the CRC Cyclic Redundant Check – the code for cyclic control is used.
The Cyclic Redundant Check (CRC16) is a cyclic verification code based on the polynomial A001h. The transmitting device forms the Cyclic Redundant Check for all bytes of the message transmitted. The receiving device similarly generates the Cyclic Redundant Check for all bytes of the message received and compares it with the Cyclic Redundant Check received from the transmitting device. In case of mismatching the generated and received Cyclic Redundant Check the error message will be generated.
The field of Cyclic Redundant Check has two bytes. CRC in the message is transferred with low byte first.
CRC is formed by the following algorithm:
- loading CRC register (16 bit) by units (FFFFh)
- exclusive OR with the first 8 bits of the byte of the message and CRC register contents
- shift of the result one bit to the right
- if shifted bit = 1, exclusive OR of the contents of the register with value A001h
- if shifted bit = 0, repeat step 3
- repeat steps 3, 4, 5, until 8 shifts
- exclusive OR with the following 8 bits byte of the message and CRC register contents
- repeat steps 3 to 7 until all bytes of the message will be processed
- the final contents of the register will contain the CRC
Example of Program CRC code generation in the language C. The function has two arguments:
unsigned char* data– a pointer to the message bufferunsigned char length– the quantity of bytes in the message buffer
The function returns the CRC value as a type of unsigned integer.
unsigned int crc_chk(unsigned char* data, unsigned char length){ int j; unsigned int reg_crc=0xFFFF; while(length--) { reg_crc ^= *data++; for(j=0;j<8;j++) { if(reg_crc & 0x01) reg_crc=(reg_crc>>1) ^ 0xA001; // LSB(b0)=1 else reg_crc=reg_crc>>1; } } return reg_crc;}5.4.5.2 Control in ASCII Mode
Section titled “5.4.5.2 Control in ASCII Mode”To check the correctness of data transfer in ASCII mode LRC Redundant Check – longitudinal redundancy check. CRC is 8-bit number transmitted as two ASCII characters. The CRC is formed by inverse transformation of all ASCII characters in eight-bit binary number, the addition of these numbers without accounting for the transfer, and the calculation of additional code of the received number. At the receiver, the LRC is calculated again and compared with the received LRC. In the calculation of LRC the colon, CR and LF are discarded.
5.4.6 Register Addresses
Section titled “5.4.6 Register Addresses”The register addresses of measured and calculated parameters of UBZ-305M are given in Table 3.5.
The register addresses of programmable parameters are given in Table 3.6.
The register addresses of special and service parameters and their purpose are given in Table 3.4.
The register address of the status and purpose bit data in Table 5.9.
The register addresses of the alarm log are given in Table 5.9.
The register addresses of time settings are given in Table 5.10.
The register address of commands is 903 (Table 5.12).
Table 5.9 – Register addresses and bit definitions
| Description | Address | Service | Remark |
|---|---|---|---|
| Register of UBZ-305M state | 900 | Bit 0: 0 – No fault; 1 – fault (code of fault in register 241) | |
| Bit 1: 0 – load relay is disabled; 1 – load relay is enabled | |||
| Bit 2: 0 – functional relay is disabled; 1 – functional relay is enabled | |||
| Bit 3: 0 – restart is disabled; 1 – ARS is waited | |||
| Bit 5-4: Mode of functional relay: 00 – alarm relay; 01 – time relay; 10 – star/delta | |||
| Bit 6: 0 – MNS mode is disabled; 1 – MNS mode is enabled | |||
| Bit 7: 0 – clock battery is normal; 1 – the clock battery should be replaced | |||
| Bit 8: 0 – not in hysteresis area; 1 – in hysteresis area when operating with analog inputs | |||
| Register of fault 1 | 901 | Bit service as per Table 5.13 | 0 – no fault; 1 – fault |
| Register of fault 2 | 902 | Bit service as per Table 5.13 | 0 – no fault; 1 – fault |
| Fault logbook | |||
| Fault code 1 | 1000 | Fault code as per Table 5.13 | |
| Parameter value 1 | 1001 | Parameter value as per Table 5.13 | |
| Fault time 1 | 1002 | Low byte – seconds, high byte – minutes | |
| 1003 | Low byte – hours, high byte – day of month | ||
| 1004 | Low byte – month, high byte – (year minus 2000) | ||
| Fault code N | 1000+(N-1)*5 | Fault code as per Table 5.13 | |
| Parameter value N | 1000+(N-1)*5+1 | Parameter value as per Table 5.13 | |
| Fault time N | 1000+(N-1)*5+2 | Low byte – seconds, high byte – minutes | |
| 1000+(N-1)*5+3 | Low byte – hours, high byte – day of month | ||
| 1000+(N-1)*5+4 | Low byte – month, high byte – (year minus 2000) |
5.4.7 Time Parameter Registers
Section titled “5.4.7 Time Parameter Registers”The parameters are transmitted in binary decimal code. For example, the code 0x14 in the register of minutes means 14 minutes.
Registers of time settings allow reading and recording of data.
Table 5.10 – Register addresses for time settings
| Parameter | Address | Remark |
|---|---|---|
| Seconds | 80 | |
| Minutes | 81 | |
| Hours | 82 | |
| Day | 83 | |
| Month | 84 | |
| Year | 85 | Last two digits of the current century are recorded (read) |
5.4.8 Communication Errors Handling
Section titled “5.4.8 Communication Errors Handling”In case of erroneous situation when making the frame (parity error, frame error, checksum error) UBZ-305M returns no reply.
In the event of an error in the format or value of data transferred (unsupported function code, etc.) UBZ-305M accepts the request frame and builds a response with a symptom and error code. The error indicator is the high bit set to one in the function field. For the error code there is separate field in the response.
Example – Request (Function 30h is not maintained):
| Address | Function | Data | CRC LB | CRC HB |
|---|---|---|---|---|
| 01h | 30h | XXh | XXh |
Response:
| Address | Function | Error code | CRC LB | CRC HB |
|---|---|---|---|---|
| 01h | B0h | 01h | 94h | 00h |
Table 5.11 – Error codes
| Error code | Name | Description |
|---|---|---|
| 01h | ILLEGAL FUNCTION | Received function code cannot be processed by UBZ-305M |
| 02h | ILLEGAL DATA ADDRESS | The data address specified in the request is not available to this slave |
| 03h | ILLEGAL DATA VALUE | The value contained in the request data field is disabled value for UBZ-305M |
| 04h | SLAVE DEVICE FAILURE | While UBZ-305M attempted to perform the requested action, unrecoverable error occurred |
| 05h | ACKNOWLEDGE | UBZ-305M accepted the request and is processing it, but this takes much time |
| 06h | SLAVE DEVICE BUSY | UBZ-305M is busy of processing a command. The master should repeat the message later |
| 07h | NEGATIVE ACKNOWLEDGE | UBZ-305M cannot perform the program function received in request |
5.4.9 Remote Control of the Motor Using USB/RS-485 Interface
Section titled “5.4.9 Remote Control of the Motor Using USB/RS-485 Interface”UBZ-305M operation in remote control mode is determined by parameter “MotorOp RS-2/5”:
- When “MotorOp RS-2/5” equal to “Off” (0) – remote control of the motor is disabled.
With activated remote control (parameter “MotorOp RS-2/5” equal to “OnSta”(1) or “OffSta” (2)), motor start on the front panel is disabled regardless of the value of the parameters “MotorOpUBZ” and “Start>power”.
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When “MotorOp RS-2/5” equal to “OnSta” – after energizing UBZ-305M operates in the same way as when the remote control is disabled (normal device operation), but it is enabled to record to the command register R_COMMAND. Automatic motor start is possible only after ARS time.
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When “MotorOp RS-2/5” equal to “OffSta” – UBZ-305M will start the motor only after the receipt of the respective command via USB/RS-485 interface.
The value R_COMMAND is taken into account by UBZ-305M operation algorithm when “MotorOp RS-2/5” =“OnSta” and “MotorOp RS-2/5” = “OffSta”. If “MotorOp RS-2/5” = “Off” and the user sets “MotorOp RS-2/5” “OnSta” or “MotorOp RS-2/5” = “OffSta”, then in R_COMMAND zero (0) will be recorded.
The list of possible register setup of commands is shown in Table 5.12.
When “MotorOp RS-2/5” = “OnSta”, then after energizing in the command register 1 is recorded (normal device operation).
When “MotorOp RS-2/5” = “OffSta”, then after energizing in the command register 0 is recorded (motor is disabled prior to entering the command to enable).
In case of emergency shutdown of the motor by simultaneously pressing DOWN, UP (when “MotorOp UBZ” = 2 (“Stop”) or “MotorOp UBZ” = 3 (“St<>”)), 0 will be reset in the command register.
Table 5.12 – Values of command register
| Command register R_COMMAND (Address = 903) | Action fulfilled |
|---|---|
| 0 | Turn off the motor. If the motor is turned off, before receiving a command from the remote control to turn on the motor will not turn on. If the motor is on, the motor will be off. |
| 1 | Normal operation of the device. If the motor has been disabled by the command of the remote control or by simultaneous pressing DOWN, UP when “MotorOp UBZ” = 3 (“St<>”) or when fault occurs, after which ARS is possible, then enabling the motor when 1 record to R_COMMAND will happen after ARS time from the moment the motor is turned off. |
| 2 | The early motor switching on. Record 2 turns on the motor before the ARS time finishes. After the motor enabling R_COMMAND =1. |
| 55 (37 Hex) | Command “FAULT RESET” (section 5.4.10) |
| 88 (58 Hex) | Command “UBZ RESTART” (“RESTART”) (section 5.4.11) |
5.4.10 Command “FAULT RESET”
Section titled “5.4.10 Command “FAULT RESET””Command “FAULT RESET” is fulfilled after recording the command code 55 in the command register (Table 5.12) via USB/RS-485 interface.
When the command is fulfilled:
- all faults are reset (whether ARS is disabled or enabled)
- ARS count ends
- if there is no current fault, the motor is enabled
5.4.11 Command “UBZ RESTART” (“RESTART”)
Section titled “5.4.11 Command “UBZ RESTART” (“RESTART”)”Command “UBZ RESTART” is used for entering into effect of the changed parameters of communication.
Command “UBZ RESTART” is fulfilled after record of command code 88 in the command register (Table 5.12) via USB/RS-485 interface. After receiving Command “UBZ RESTART”, UBZ-305M does not return confirmation of received command.
5.4.12 UBZ-305M Factory Settings Using MODBUS Interface
Section titled “5.4.12 UBZ-305M Factory Settings Using MODBUS Interface”To do this, you need to set the parameter “Default Factor” = 1. In this case the operation parameters of the serial interface will not change (reset of interface settings to factory settings is not performed). The execution time of reset to the factory setting is to 5 seconds. After the operation finished the parameter “Default Factor”=0.
5.5 Emergency Conditions System
Section titled “5.5 Emergency Conditions System”In case of emergency state of UBZ-305M:
- in the fourth line of the indicator the alarm message displays (Figure 5.14) (fault code corresponds to Table 5.13)
- red LED “FAULT” is on (with constant light if ARS is disabled and with flashing, if ARS is expected)
- the load relay is disabled
- functional relay is activated (when “Relay F Mode” = “Alarm”)

Figure 5.14 – UBZ-305M Indicator in mode of view for measured and calculated parameters (if there is a fault)
If UBZ-305M defines several different types of faults at the same time, the codes of faults and parameter values are displayed sequentially, one by one (on the indicator the number of displayed fault is changed).
If ARS is enabled, then in the fourth line of the indicator alternately the codes of faults and the time in seconds remaining until ARS are shown (Figure 5.15) (if the waiting time for thermal overload of the motor is more than the ARS time, then the waiting time is displayed). If ARS is disabled, the state of ARS in the third line is not displayed.

Figure 5.15 – Indicator when displaying the time remaining until ARS
Table 5.13 – Fault codes
| Fault description | Fault mnemonics | Parameter value | Register address of parameter value | Fault code | Register address of faults for N bit |
|---|---|---|---|---|---|
| Maximum phase current | I max | Maximum phase current | 300 | 0 | 901:0 |
| Thermal overload | Thermal over | 301 | 1 | 901:1 | |
| Ground fault (zero sequence current) | Iearth | Zero sequence current | 302 | 2 | 901:2 |
| Excess ratio of negative sequence current to negative sequence voltage | Coef I/U | Coefficient × 100 | 303 | 3 | 901:3 |
| Negative sequence current | I2 rev | Negative sequence current | 304 | 4 | 901:4 |
| Minimum phase current | I min | 305 | 5 | 901:5 | |
| Delayed start | LongStart | Current | 306 | 6 | 901:6 |
| Rotor blocking | Block Rot | Current | 307 | 7 | 901:7 |
| Upon reaching the temperature threshold of the first transmitter | Temp1 | Temperature in degrees | 308 | 8 | 901:8 |
| Upon reaching the temperature threshold of the second transmitter | Temp2 | Temperature in degrees | 309 | 9 | 901:9 |
| Phase sequence | PhaseSequen | 310 | 10 | 901:10 | |
| External MS (presence of currents when load relay is disabled) | Contactor | Current | 311 | 11 | 901:11 |
| At minimum line voltage | U min | Voltage | 312 | 12 | 901:12 |
| At maximum line voltage | U max | Voltage | 313 | 13 | 901:13 |
| At phase imbalance | Uimbal | Imbalance | 314 | 14 | 901:14 |
| Minimum insulation resistance of motor winding | Insul Res | Insulation resistance | 315 | 15 | 901:15 |
| Mains minimum frequency | F min | Frequency | 316 | 16 | 902:0 |
| Mains maximum frequency | F max | Frequency | 317 | 17 | 902:1 |
| Fault of remote control channel | RemoteCont | 18 | 902:2 | ||
| Motor emergency shutdown without possibility for restart | Stop nAR | 19 | 902:3 | ||
| Motor emergency shutdown with possibility to restart by pressing UP+DOWN | Stop Motor | 20 | 902:4 | ||
| S.c. of temperature transmitter 1 | ShortTempS1 | 21 | 902:5 | ||
| Breakout of temperature transmitter 1 | BreakTempS1 | 22 | 902:6 | ||
| S.c. of temperature transmitter 2 | ShortTempS2 | 23 | 902:7 | ||
| Breakout of temperature transmitter 2 | BreakTempS2 | 24 | 902:8 | ||
| Loss of phase | Break Phase | 25 | 902:9 | ||
| EEPROM destruction | Error EEPROM | 26 | 902:10 | ||
| At analog input “0-20 mA” | Input I | 327 | 27 | 902:11 | |
| At analog input “0-10 V” | Input U | 328 | 28 | 902:12 | |
| Improper calibration | Error CALIB | 29 | 902:13 |
Notes:
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Occurrence of fault as “EEPROM Error” – the destruction of EEPROM indicates that the data of the programmed parameters (Table 3.6) is damaged. To continue the operation, it is necessary to turn off UBZ-305M and restore the factory settings (section 5.2.7 – second method).
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Occurrence of fault as “Error CALIB” – UBZ-305M improper calibration means that the calibration coefficients of the measured data are damaged. The continued operation of UBZ-305M is impossible. Re-calibration of the device is required to be done at the manufacturer factory.
5.6 Emergency Conditions Logbook
Section titled “5.6 Emergency Conditions Logbook”When disabling the load relay in the event of fault, UBZ-305M records in its memory the code of the fault, the value of the parameter on which the fault occurred and time of occurrence.
Number of simultaneously stored fault codes is 50. In case of subsequent faults occur, the fault information is recorded in place of the oldest fault.
To view the log, it is necessary to press button “WR/SEL”.
LED “SETUP” will on in flashing mode, and UBZ-305M indicators will display the latest fault (Figure 5.16).

- Line 1 – indication of mode (alarm logbook)
- Line 2 – number of the fault (1 – means the most recent fault)
- Line 3 – mnemonic of the fault as per Table 5.13 and the parameter value at the moment of the fault occurrence
- Line 4 – time and date of the fault
Figure 5.16 – Display in the view mode of the fault logbook
View the fault logbook by pressing the UP or DOWN button.
To exit the view log mode, press the button “WR/SEL” or exit will be automatically in 30 seconds after the last pressing of any button.
Register addresses to read data log of faults via MODBUS Protocol are given in Table 5.9.
5.7 Motor Control on UBZ-305M Front Panel
Section titled “5.7 Motor Control on UBZ-305M Front Panel”Depending on the value of the parameter “MotorOp UBZ”, you can control the load relay of UBZ-305M by simultaneously pressing the UP and DOWN buttons:
- “Off” – no reaction
- “Start” (motor start is enabled) – the load relay will be enabled if ARS time has not finished
- “Stop” (motor emergency shutdown) – the load relay will be disabled with the issuance of fault code “Stop nAR”. The restart of the motor is possible only after de-energizing and re-energizing of UBZ-305M unit
- “St<>” (motor start and shutdown is permitted) – the load relay is disabled with issuance of code “Stop Motor”. To enable it, press again UP and DOWN buttons
5.8 Motor Control Using Analog Inputs
Section titled “5.8 Motor Control Using Analog Inputs”The motor control algorithms by the analog inputs “0-20 mA” and “0-10 V” are shown in Table 3.6.
After the motor stopping according to emergency level the countdown for ARS will only start after going out the parameter value of the emergency zone.
If after the motor switching off by the alarm level the parameter value is between the levels on and off for the motor, then:
- indicator “Motor” blinks
- indicator “FAULT” is off
- the fault code is displayed on LCD
6. Maintenance
Section titled “6. Maintenance”6.1 Safety Precautions
Section titled “6.1 Safety Precautions”Maintenance of the unit should be performed by persons admitted to the operation and have the appropriate permission. The recommended frequency of maintenance is every six months.
6.2 Maintenance Procedure
Section titled “6.2 Maintenance Procedure”- Check the wires connection reliability, if necessary – clamp with force as specified in Table 3.1
- Check visually the housing integrity
- If necessary, wipe with cloth the front panel and the unit housing
7. Transportation and Storage
Section titled “7. Transportation and Storage”UBZ-305M in the original package of the Manufacturer should be stored indoors with temperature from minus 45 to +60°C and relative humidity of not more than 80% in the absence of vapors harmfully acting on the packaging and materials of the device.
During transportation of UBZ-305M, the consumer should protect the unit from mechanical damage.
8. Service Life, Shelf Life and Manufacturer Warranty
Section titled “8. Service Life, Shelf Life and Manufacturer Warranty”8.1 The unit service life is 10 years. Upon expiration of the service life you should contact the Manufacturer.
8.2 Shelf life is 3 years.
8.3 Warranty period of the unit operation is 5 years from the date of sale.
During the warranty period the Manufacturer is responsible for free repair of the unit, if the Consumer has complied with the requirements of this Operation Manual.
8.4 Warranty service is performed at the place of purchase or by the Manufacturer of the Unit.
8.5 Post-warranty service is performed by the Manufacturer at current rates.
8.6 Before sending for repair, the unit should be packed in the original or other packaging excluding mechanical damage.
For all questions, please contact the Manufacturer:
“Novatek-Electro” Ltd.
- Website: www.novatek-electro.com
- Address: 59, Mykhailo Boltenko (Admiral Lazarev) str., Odesa, Ukraine, 65007
- Tel: +38 (067) 565 37 68; +38 (050) 359 39 11; +38 (063) 301 30 40