Quick Start and Application Setup

This guide takes the OB-216 from an unpowered installation to a verified Modbus reading. It also shows which input, operating mode, settings, and result register belong together for each supported application.

Read the safety instructions first

Before installing the OB-216, read the safety precautions in the operating manual. Make or change terminal connections only while the OB-216, sensors, and connected equipment are de-energized.

Understand the device before wiring

Terminals serve one function at a time

The OB-216 is a single-channel, configurable device. Its terminals can be used for different applications, one at a time. It is not possible to perform all of them at the same time.

• Connect one input source or sensor at a time.
• Select one input operating mode in register 100.
• The input terminals used (and result register address) depend on that mode.
• The voltage and current analog outputs are two forms of the same output channel. Configure only the required output type.
• USB and RS-485 are alternative communication interfaces. With factory settings, connecting USB selects USB and disables RS-485 until the USB connection is removed.

USB does not replace the device power supply

Power the OB-216 from an isolated 10–30 V DC supply connected to its power terminals. The microUSB connection is used for communication with a PC.

Choose the input application

Use this table before connecting anything.

Application	Input terminals / diagram	Register 100 / Mode of operation	Register 101 / Plugged-in digital sensor	Additional settings	Read the result at
0–10 V sensor	IO1, Figure 2(b)	2, meas. voltage		Optional: 104–105, 130–134	Measured value 6; converted value 16
0–20 mA sensor	IO1, Figure 2(a)	3, meas. current		Optional: 104–105, 130–134	Measured value 6; converted value 16
NTC 10KB	IO2, Figure 2(c) / sensor connection diagram	4, NTC sensor (10 KB)		Optional: 102, 104–105	Measured value 6
PTC 1000	IO2, Figure 2(c) / sensor connection diagram	5, PTC1000 sensor		Optional: 102, 104–105	Measured value 6
PT 1000	IO2, Figure 2(c) / sensor connection diagram	6, PT1000 sensor		Optional: 102, 104–105	Measured value 6
DS18B20	Figure 3	8, digital sensor	0, DS18B20	Optional: 102–105	Temperature 11
DHT11	Figure 3	8, digital sensor	1, DHT11	Optional: 102–105	Temperature 11; humidity 12
DHT21 / AM2301	Figure 3	8, digital sensor	2, DHT21 / AM2301	Optional: 102–105	Temperature 11; humidity 12
DHT22	Figure 3	8, digital sensor	3, DHT22	Optional: 102–105	Temperature 11; humidity 12
Dry-contact state	IO2, Figure 2(d)	1, LOG input		Register 107: debounce	Status register 2:3, bit 18
Dry-contact or transistor pulses	IO2, Figure 2(e)	0, pulse counter		Registers 106–108	Counter 4:5
Voltage pulses	IO1, Figure 2(f)	11, counter pul. voltage		Registers 104–106, 108	Counter 4:5
Current pulses	IO1, Figure 2(f)	12, counter pul. current		Registers 104–106, 108	Counter 4:5
No sensor, remote manual output	IO1 / IO2 unconnected	1

The wiring figures referenced above are reproduced in the relevant procedures below. The complete register definitions are in OB-216 settings and Additional Registers.

Initial connection and configuration

What you need

• OB-216 and the supplied microUSB cable
• Galvanically isolated 10–30 V DC power supply
• 35 mm DIN rail to mount the OB-216 on
• 0.5–3.0 mm² conductors, ferrules, and suitable tools
• The one sensor, contact, pulse source, or analog load required by the application
• Twisted-pair cable for RS-485, if used
• A Windows PC with the Control Panel OB-215/OB-216 application
• The NOVATEK USB-SERIAL driver, if Windows does not recognize the USB interface

De-energize before wiring

Disconnect power from the OB-216 and all connected circuits before inserting, removing, or moving any conductor. Tighten terminal screws to 0.4 N·m.

1. Select the application

   Find the required application in the table above. Record the operating-mode value for register 100, the connection figure, any additional settings, and the result register. This avoids configuring one mode while wiring another.

2. Mount and wire the OB-216

   Mount the device on a 35 mm DIN rail. While all circuits are de-energized, connect the isolated 10–30 V DC supply and then connect only the sensor or signal source for the selected application.

   Do not connect a digital sensor, a 0–10 V source, a 0–20 mA source, and a temperature sensor simultaneously. They are alternative uses of the input.

3. Connect the PC for initial setup

   Connect the microUSB cable between the OB-216 and the PC. Install the NOVATEK USB-SERIAL driver if the interface is not detected, then start Control Panel OB-215/OB-216.

4. Apply power and establish communication

   Apply 10–30 V DC power. The power indicator flashes for approximately 1.5 seconds during startup. At factory settings, the OB-216 automatically selects USB when the cable is connected.

   Factory communication settings are:

   Setting	Factory value
   Modbus protocol	RTU
   Modbus unit ID	28
   Baud rate	9600 bit/s
   Parity / stop bits	No parity, 2 stop bits
   Interface selection	Automatic

5. Set the input mode and application parameters

   Set register 100 to the value selected in the application table. Configure the sensor type, thresholds, debounce, scaling, or output settings required by that procedure.

6. Save the settings

   Write 18220 to command register 50. The OB-216 saves the settings to flash memory, restarts, and begins operating with the new configuration.

   Caution

   Changing settings without sending the save command leaves status-register bit 29 set, and the changes may be lost after power removal.

7. Verify the measurement locally

   Read register 0; the expected device identifier is 28. Then read the result register listed for the application. Check the relevant status bit where applicable. Do not proceed to a controller or production network until the locally read input value is plausible.

8. Move to RS-485, if required

   Remove power, disconnect the USB cable, and connect the RS-485 twisted pair: A is the non-inverted signal and B is the inverted signal. Reapply power and configure the Modbus master to exactly match the OB-216 protocol, unit ID, baud rate, parity, and stop bits.

   USB and RS-485 dependency

   In automatic interface mode (register 113 = 0), a connected USB cable makes the OB-216 use USB and turns off RS-485. Disconnect USB before testing RS-485. Alternatively, set Data interface register 113 to 1 for RS-485 only or 2 for USB only, save, and restart.

Application procedures

0–10 V sensor (PLC / VFD output or other transmitter)

Use this procedure for a sensor whose output voltage is within 0–10 V.

1. De-energize all equipment and wire the voltage source as shown in Figure 2(b). Confirm that the source cannot exceed the OB-216 supply voltage. For correct measurement of high input values (near 10V), a 12V-24V supply is recommended.
2. Set register 100 to 2 (that is Mode of operation = meas. voltage).
3. If required, set the upper threshold in register 104 and lower threshold in register 105. These affect status bits 20 and 21 only, reporting values outside these thresholds.
4. Save settings by writing 18220 to register 50 and allow the OB-216 to restart.
5. Read register 6. Voltage uses hundredths of a volt, so the value would be in 0-1000 range: 500 means 5.00 V.
6. If unit conversion is required, set register 130 to 1 and configure registers 131–134 with the input and converted ranges. Read the scaled result from register 16, then save the settings again.

Example — 0.5–8 V pressure sensor representing 1–25 bar: set registers 131–134 to 50, 800, 1, and 25. Read pressure from register 16. Use 10 and 250 if a single fractional digit is required, etc.

0–20 mA sensor or transmitter

1. De-energize all equipment and wire the current loop as shown in Figure 2(a). Check the sensor documentation to determine whether an external loop supply is required. For correct measurement of high input values (near 20mA), a 12V-24V supply is recommended.
2. Set register 100 to 3 (that is Mode of operation = meas. current).
3. If required, set the upper threshold in register 104 and lower threshold in register 105. These affect status bits 22 and 23 only, reporting values outside these thresholds.
4. Save settings by writing 18220 to register 50 and allow the OB-216 to restart.
5. Read register 6. Current uses hundredths of a milliampere, so the value would be in 0-2000 range: 450 means 4.50 mA.
6. If unit conversion is required, set register 130 to 1, configure registers 131–134, and read the scaled result from register 16. Save the settings again.

Example — 4.5–20 mA pressure sensor representing 1–25 bar: set registers 131–134 to 450, 2000, 1, and 25.

NTC 10KB, PTC 1000, or PT 1000 analog temperature sensor

1. De-energize the OB-216 and connect one analog temperature sensor using Figure 2(c) and the sensor connection diagram above.
2. Set Mode of operation register 100 according to the sensor: 4 for NTC 10KB, 5 for PTC 1000, or 6 for PT 1000.
3. If a known temperature correction must be applied, set register 102 in tenths of a degree. For example, 5 adds 0.5 °C and -5 subtracts 0.5 °C.
4. Optionally set the upper and lower temperature thresholds in registers 104 and 105. These affect status bits 24 and 25 only, reporting values outside these thresholds.
5. Save settings by writing 18220 to register 50 and allow the OB-216 to restart.
6. Read the temperature from register 6 as tenths of a degree Celsius: 234 means 23.4 °C.

DS18B20 digital temperature sensor

1. De-energize the OB-216. Connect one DS18B20 as shown above.
2. Install an external 2–5.1 kΩ pull-up resistor between the sensor Data line and its supply line.
3. Set register 100 to 8 (that is Mode of operation = digital sensor) and digital-sensor register 101 to 0 (DS18B20).
4. If a known temperature correction must be applied, set register 102 in tenths of a degree. For example, 5 adds 0.5 °C and -5 subtracts 0.5 °C.
5. Optionally set the upper and lower temperature thresholds in registers 104 and 105. These affect status bits 24 and 25 only, reporting values outside these thresholds.
6. Save by writing 18220 to register 50 and allow the OB-216 to restart.
7. Wait at least 3 seconds for a sensor poll, then read temperature from register 11 in tenths of a degree Celsius.

DHT11, DHT21 / AM2301, or DHT22 sensor

1. De-energize the OB-216. Connect one DHT sensor as shown in the digital-sensor wiring diagram.
2. Install an external 2–5.1 kΩ pull-up resistor between the sensor Data line and its supply line.
3. Set register 100 to 8 (that is Mode of operation = digital sensor).
4. Set register 101 to 1 for DHT11, 2 for DHT21 / AM2301, or 3 for DHT22.
5. Select with register 103 the parameter used for thresholds and automatic-output operation: 0 for temperature or 1 for humidity. This selection does not prevent reading both available measurements.
6. If a known temperature correction must be applied, set register 102 in tenths of a degree. For example, 5 adds 0.5 °C and -5 subtracts 0.5 °C.
7. Optionally set the upper and lower thresholds in registers 104 and 105. These affect status bits 24 and 25 (for temperature selection) or 26 and 27 (for humidity selection) only, reporting values outside these thresholds.
8. Save by writing 18220 to register 50 and allow the OB-216 to restart.
9. Wait at least 3 seconds. Read temperature from register 11 in 0.1 °C and humidity from register 12 in 0.1% RH. For example, humidity value 800 means 80.0% RH.

Dry-contact state input

1. De-energize the OB-216 and connect the dry contact to IO2 as shown in Figure 2(d).
2. Set register 100 to 1 (that is Mode of operation = LOG input).
3. Set Contact bounce suppression in register 107 to a value in range 1-250 ms (if the factory value of 10 ms is unsuitable).
4. Save by writing 18220 to register 50 and allow the OB-216 to restart.
5. Read the 32-bit status value from registers 2:3. Bit 18 is 1 when IO2 is closed and 0 when it is open.

Pulse counter

Choose the pulse mode that matches the signal source:

Pulse source	Register 100 / Mode of operation	Maximum frequency	Thresholds
Dry contact / discrete signal on IO2	0, pulse counter	200 Hz	Not used
Voltage pulses on IO1	11, counter pul. voltage	10 Hz	Registers 104–105
Current pulses on IO1	12, counter pul. current	10 Hz	Registers 104–105

1. De-energize the OB-216 and wire the source as shown in Figure 2(e) for a discrete signal or Figure 2(f) for voltage/current pulses.
2. If a discrete source has a PNP output, install the external 1–5.1 kΩ resistor shown in Figure 2(e).
3. Set register 100 to 0, 11, or 12 according to the table above.
4. Set register 106 to 0 for leading edges, 1 for trailing edges, or 2 for both edges.
5. For mode 0 (pulse counter), set the Contact bounce suppression in register 107.
6. For modes 11 and 12, set the upper and lower detection thresholds in registers 104 and 105. These are used for pulse detection, with a valid pulse alternately crossing both thresholds.
7. Set register 108 to the number of input pulses represented by one counter increment. Changing register 108 clears stored counter values.
8. If a non-zero starting count is required, write it to 32-bit registers 4:5.
9. Save by writing 18220 to register 50 and allow the OB-216 to restart.
10. Generate known pulses and read the 32-bit count from registers 4:5.

Counter storage

The counter is saved to flash once per minute; a value accumulated for less than one minute may be lost if power is removed.

Analog output

The analog output can operate in one of two modes:

• automatically follow the selected input;
• manually set by Modbus.

Required output	Register 150 / Work permit	Full-scale register maximum value	Additional settings
0–10 V automatic	1, voltage - auto	1000 = 10.00 V	Input range 153–154, output range 155-156
0–20 mA automatic	2, current - auto	2000 = 20.00 mA	Input range 153–154, output range 155-156
0–10 V manual	3, voltage - manual	1000 = 10.00 V	Converting manual values 152, optionally conversion ranges 153–156
0–20 mA manual	4, current - manual	2000 = 20.00 mA	Converting manual values 152, optionally conversion ranges 153–156

Automatic output

1. First configure and verify the input application.
2. Set register 150 to 1 for voltage or 2 for current.
3. Set the input range in registers 153–154 and corresponding analog output range in registers 155–156. For example, to convert 4-20 mA sensor into 0-20 mA, use 400 and 2000 for registers 153–154, and 0 and 2000 for registers 155–156.
4. Save by writing 18220 to register 50.
5. Read register 17 and measure the physical output to verify the conversion.

Manual output

1. Set register 150 to 3 for voltage or 4 for current.
2. For direct values, set register 152 to 0, then write the required output to register 151. For example, 500 produces 5.00 V or 5.00 mA according to the selected output mode.
3. For scaled control, set register 152 to 1 and configure the input/output ranges in registers 153–156 before writing the command value to register 151. For example, to convert 1.0-25.0 bar range into 0.5-8 V, use ranges 10 and 250 for registers 153–154, and 50 and 800 for registers 155–156. Write the pressure value in tenths of a bar to register 151.
4. Save the mode and conversion settings by writing 18220 to register 50.
5. Set the register 151 (Manual control value) and verify the output with a suitable meter before connecting the final load.

Caution

Confirm the receiving equipment’s accepted voltage/current range before enabling the output. An incorrect range or output type can damage connected equipment.

Connect the load to the current output (Figure 1, terminal 9) or voltage output (Figure 1, terminal 10), together with analog ground (terminal 8).

Read the safety instructions first

Connect the external load to only one output: voltage or current, but not both.

Verification checklist

Before considering setup complete, verify all of the following:

• Only the intended single sensor or signal source is connected to the input.
• Register 100 matches the wiring and sensor type.
• Register 101 matches the digital sensor, if used.
• The result is read from the correct register and interpreted with the correct scale.
• The value is plausible when tested at two known input points or states.
• Settings were saved by writing 18220 to register 50.
• Status bit 29 is 0, indicating settings are saved.
• USB is disconnected before RS-485 testing in automatic interface mode.
• The Modbus master matches unit ID, protocol, baud rate, parity, and stop bits.
• Each device on a multidrop RS-485 network has a unique unit ID.
• Only the intended single load or signal input is connected to the output.

Troubleshooting

Q: Why is there no communication over USB?

A: Confirm the 10–30 V supply is present, install the USB-SERIAL driver, and check that register 113 is not forced to RS-485 only.

Q: Why is there no communication over RS-485?

A: Disconnect USB, check A/B polarity, and make sure the unit ID, protocol, baud rate, parity, and stop bits match. Check that register 113 is not set to USB only.

Q: Why does the reading never change?

A: Confirm that register 100 matches the wiring, verify that you are reading the correct result register, and check the sensor power and common connection.

Q: Why does the digital sensor have no valid reading?

A: Confirm that register 100 is set to 8 and register 101 matches the sensor. Install the 2–5.1 kΩ pull-up resistor and wait at least 3 seconds for a reading.

Q: Why is the analog value incorrect by a factor of 10 or 100?

A: Apply the register scaling shown in the relevant application procedure. Make sure you distinguish raw register 6 from converted register 16.

Q: Why is the threshold status unexpected?

A: For DHT sensors, check register 103. Also check the upper and lower values and their units in registers 104–105.

Q: Why do new settings disappear after power loss?

A: Write 18220 to register 50 to save the settings, then verify that status bit 29 becomes 0.

Q: Why is the pulse count too high or too low?

A: Check edge selection (register 106), debounce (register 107), pulses per increment (register 108), the frequency limit, and the thresholds for voltage or current pulse modes.

Reference

• Operating Manual — complete specifications, installation, operation, and wiring diagrams
• OB-216 settings register table — all configurable parameters and valid ranges
• Status register — operating mode and alarm bits
• Command and additional registers — save, restart, measured values, and counters