GE Industrial Solutions MX350 Communications Guide - Manual (Page 14)

10 MX350 AUTOMATIC TRANSFER CONTROL SYSTEM – COMMUNICATIONS GUIDE
RS485 INTERFACE (MODBUS RTU) COMMUNICATIONS GUIDE
Function Code 06H Modbus Implementation: Preset Single Register
MX350 Implementation: Store Single Setpoint
This command allows the master to store a single setpoint into the memory of a MX350
The slave response to this function code is to echo the entire master transmission.
For example, request slave 17 to store the value 2 in setpoint address 04 5C. After the
transmission in this example is complete, setpoints address 04 5C will contain the value
01F4. The master/slave packet format is shown below:
Table 5: MASTER/SLAVE PACKET FORMAT FOR FUNCTION CODE 06H
Function Code 08H Modbus Implementation: Loopback
Test MX350 Implementation: Loopback Test
This function is used to test the integrity of the communication link. The MX350 will echo
the request.
For example, consider a loopback test from slave 17:
Table 6: MASTER/SLAVE PACKET FORMAT FOR FUNCTION CODE 08H
MASTER TRANSMISSION BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message for slave 17
FUNCTION CODE 1 06 store single setpoint
DATA STARTING ADDRESS 2 04 5C setpoint address 04
5C
DATA 2 00 02 data for setpoint
address 04 5C
CRC 2 CB B9 CRC error code
SLAVE RESPONSE BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message from slave
17
FUNCTION CODE 1 06 store single setpoint
DATA STARTING ADDRESS 2 04 5C setpoint address 04
5C
DATA 2 00 02 data stored in
setpoint address 04
5C
CRC 2 CB B9 CRC error code
MASTER TRANSMISSION BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message for slave 17
FUNCTION CODE 1 08 loopback test
DIAG CODE 2 00 00 must be 00 00
DATA 2 00 00 must be 00 00
CRC 2 E0 0B CRC error code
SLAVE RESPONSE BYTES EXAMPLE DESCRIPTION
SLAVE ADDRESS 1 11 message from slave
17
FUNCTION CODE 1 08 loopback test
DIAG CODE 2 00 00 must be 00 00
DATA 2 00 00 must be 00 00
CRC 2 E0 0B CRC error code