Instruction manual

7. MODBUS
IMS01J02-E1
117
7.2.3 Diagnostics (Loopback test) [08H]
The master’s query message will be returned as the response message from the slave.
This function checks the communication system between the master and slave (SR Mini HG SYSTEM
control unit).
Example: Loopback test for slave address 1
Query message
Slave address 01H
Function code 08H
Test code High 00H
Low 00H
Data High 1FH
Low 34H
CRC-16 High E9H
Low ECH
Normal response message
Slave address 01H
Function code 08H
Test code High 00H
Low 00H
Data High 1FH
Low 34H
CRC-16 High E9H
Low ECH
Error response message
Slave address 01H
80H + Function code 88H
Error code 03H
CRC-16 High 06H
Low 01H
Test code must be set to “00”
Contents will be the same as query message data
Any pertinent data