ERSA i-tool protocol and interface schematics

Found very good article writen by hamilsan here at Habr: https://habr.com/ru/post/369947/

Will duplicate the info here as backup and later add some addition info.

I-tool pinout:

Control unit I/o schematics:

 

UART specs:

• 250000 bps
• start bits: 1
• data bits: 8
• parity: no
• stop bits: 1

request packet:

	data type	example	description
0	u16	0x2F02	preambula(constant)
2	u8	0x05	message ID
3	u16	0x0010	Code of operation
5	u8	0x05	data length
6	u16	0x498E	crc

response packet:

	data type	example	description
0	u16	0x2F02	preambula(constant)
2	u8	0x0A	message ID
3	u16	0x0010	Code of operation (from request  packet)
5	u8	0x05	data length
6	array	0x5E 0x0A 0x1C 0x03 0x00	data
n-2	u16	0x8F42	crc

Messages

Tool detection

Control unint sent this type of message each second  (1 Hz) aftre powering up till receiving tool response.

Request:

• message ID: 0x05
• Code of operation: 0x0001
• Data Length: 2

Response:

• message ID: 0x07
• Data:
  • 0x2802: i-Tool

Example:

• Request(hex): 02 2F ' 05 ' 01 00 ' 02 ' 3A 4D
• Response(hex): 02 2F ' 07 ' 01 00 ' 02 ' 02 28 ' C1 A4

Tool version detection

One request after tool detection.

Request:

• message ID: 0x05
• Code of operation: 0x0040
• Data Length: 2

Response:

• message ID: 0x07
• Data:
  • [0]: (u8) Minor
  • [1]: (u8) Major

Example:

• Request(hex): 02 2F ' 05 ' 40 00 ' 02 ' A7 67
• Response(hex): 02 2F ' 07 ' 40 00 ' 02 ' 00 01 ' D1 CC
  • Minor: 0
  • Major: 1

Tool status

50Hz sample rate.

Request:

• message ID: 0x05
• Code of operation: 0x0010
• Data Length: 5

Response:

• message ID: 0x0A
• Data :
  • [0]: (u16) Temperature of the hot thermocouple junction(°C * 10)
  • [2]: (u8) Temperature of the cold thermocouple junction(°C)
  • [3]: (u16) flags (see further)

Flags:

15…2	1	0
RESERVED	IDLE	OK

 

• RESERVED
• IDLE: 1 — no tool movement
• OK: 1 — no errors

Example:

• Request(hex): 02 2F ' 05 ' 10 00 ' 05 ' 8E 49
• Response(hex): 02 2F ' 0A ' 10 00 ' 05 ' 52 0A ' 1C ' 03 00 ' 69 04
  • Temperature of the hot thermocouple junction: 0x0A52 = 264.2 °C
  • Temperature of the cold thermocouple junction: 0x1C = 28°C
  • Flags: 0x0003 = IDLE | OK

CRC detection

CRC16 used  –  CRC-CCITT, XModem.

Example:

CRC-CCITT-XModem(0x02 0x2F 0x05 0x10 0x00 0x05) = 0x498E