Function Code 08 - Loopback Test - GE Power Quality Meter Series Instruction Manual

7 MODBUS COMMUNICATIONS
Modbus Implementation: Loopback Test
PQM Implementation: Loopback Test
This function is used to test the integrity of the communication link. The PQM will echo the request.
MESSAGE FORMAT AND EXAMPLE:
Loopback test from slave 11.
Table 7–6: MASTER/SLAVE PACKET FORMAT FOR FUNCTION CODE 08H
MASTER TRANSMISSION
SLAVE ADDRESS
FUNCTION CODE
DIAG CODE
DATA
CRC
SLAVE RESPONSE
SLAVE ADDRESS
FUNCTION CODE
DIAG CODE
DATA
CRC
GE Power Management
7.2.7 FUNCTION CODE 08 – LOOPBACK TEST
BYTES EXAMPLE
1 11
1 08
2 00 00
2 00 00
2 E0 0B
BYTES EXAMPLE
1 11
1 08
2 00 00
2 00 00
2 E0 0B
PQM Power Quality Meter
7.2 MODBUS FUNCTIONS
DESCRIPTION
message for slave 17
loopback test
must be 00 00
must be 00 00
CRC error code
DESCRIPTION
message from slave 17
loopback test
must be 00 00
must be 00 00
CRC error code
7
7-9