ABB TMD-T4 Instruction Manual - page 7
TMD-T4
protocol communication - instruction manual IM148-U-AB v0.92 pag. 7 / 12
DIAGNOSTIC (Function Code $ 08)
This function provides a test for checking the communication system.
Broadcast is not supported.
The instrument’s protocol has only the sub-function 0 of the diagnostics sub-functions set of the standard modbus
protocol.
The Query and the Response messages are the following:
QUERY:
START OF
FRAME
ADDRESS
FIELD
FUNCTION
CODE
SUB
FUNCTION
DATA
ERROR
CHECK
END OF
FRAME
START OF FRAME
= Starting message marker.
ADDRESS FIELD
= TMD device address (01...F7 HEX)
(1 byte).
FUNCTION CODE
= Operation code ( 08 HEX)
(1 byte).
SUB FUNCTION
= Sub-function 0 (00 00 hex)
(2 byte).
DATA
= Max 10 data bytes.
ERROR CHECK
= Check sum.
END OF FRAME
= End message marker.
RESPONSE:
The response must be the loopback of the same data.
START OF
FRAME
ADDRESS
FIELD
FUNCTION
CODE
SUB
FUNCTION
DATA
ERROR
CHECK
END OF
FRAME
START OF FRAME
= Starting message marker.
ADDRESS FIELD
= TMD device address (01...F7 HEX)
(1 byte).
FUNCTION CODE
= Operation code ( 08 HEX)
(1 byte).
SUB FUNCTION
= Sub-function 0 (00 00 hex)
(2 byte).
DATA
= Data bytes.
ERROR CHECK
= Check sum.
END OF FRAME
= End message marker.
DIAGNOSTIC EXAMPLE
QUERY
RESPONSE
Field Name
Example ( Hex)
Field Name
Example ( Hex)
Slave Address
01
Slave Address
01
Function Code
08
Function Code
08
Sub-function Hi
00
Sub-function Hi
00
Sub-function Lo
00
Sub-function Lo
00
Data Hi
F1
Data Hi
F1
Data Lo
A7
Data Lo
A7
Error Check (CRC)
??
Error Check (CRC)
??
??
??