EXT0001: Device Parameters

• Extension dependencies: none
• Document status: Approved (2020-02-01)

This extension describes reading and setting device parameters (setpoints/settings). Parameters are stored in persistent memory. To optimize work with many records and eliminate intermediate states, the extension supports transactions—changes are saved in RAM first, then written to permanent memory when the transaction completes.

Commands

0002 Read Parameters

Read a block of parameters from persistent memory.

Request:

<TID> 3900 <LEN> 0002 <SOURCE> [( <OFFSET> <BLOCKLEN> ) ...]

If OFFSET and BLOCKLEN are not specified, returns maximum data without offset. Multiple pairs can be specified for multiple blocks in response.

Response:

<TID> 3900 <LEN> 0002 (<BLOCKDATA>) ...

Field	Length	Description
SOURCE	1 byte	Data source
OFFSET	2 bytes	Offset in parameter structure
BLOCKLEN	2 bytes	Block length
BLOCKDATA	BLOCKLEN	Parameter block bytes

Errors:

Code	Description
0010	Incorrect SOURCE
0011	Reading out of bounds
0012	Response overflow
0013	ROM read error

0003 Write Parameters

Write parameters and manage transactions.

When initialized, the device allocates RAM for the parameter structure and copies from permanent memory. Changes accumulate in RAM. Device keeps the structure for at least 10 seconds. On transaction completion (TRCON = 2), changes are written to permanent memory.

Request:

<TID> 3900 <LEN> 0003 <SOURCE> <TRCON> [( <OFFSET> <BLOCKLEN> <BLOCKDATA> ) ...]

Response:

<TID> 3900 0002 0003

Field	Length	Description
SOURCE	1 byte	Data source
TRCON	1 byte	Transaction control: 0=start new, 1=continue, 2=commit
OFFSET	2 bytes	Offset in parameter structure
BLOCKLEN	2 bytes	Block length
BLOCKDATA	BLOCKLEN	Parameter block bytes

Errors:

Code	Description
0010	Incorrect SOURCE
0011	Writing out of bounds
0012	ROM write error
0013	ROM resource expired
0014	RAM error (can’t allocate)
0015	Transaction aborted by another connection
0016	Transaction timeout
0017	Attempting to continue completed transaction