Function Code 08H; Function Code 10H - GE Multilin MM3 Motor Manager 3 Instruction Manual

SUPPORTED MODBUS FUNCTIONS
8.2.8 Function Code
08h
8.2.9 Function Code
10h
8–10
Modbus implementation: Loopback test
MM3 Motor Manager 3 implementation: Loopback test
This function is used to test the integrity of the communication link. The MM3 Motor
Manager 3 will echo the request. For example, consider a loopback test from slave 17:
Master Transmission
Slave address
Function code
Diagnostic code
Data
CRC
Slave Response
Slave address
Function code
Diagnostic code
Data
CRC
Modbus implementation: Preset multiple registers
MM3 Motor Manager 3 implementation: Store multiple setpoints
This function code allows multiple setpoints to be stored into the MM3 Motor Manager 3
memory. Modbus registers are 16-bit (two byte) values transmitted high order byte first.
Thus all MM3 Motor Manager 3 setpoints are sent as two bytes. The maximum number of
setpoints that can be stored in one transmission is dependent on the slave device. Modbus
allows up to a maximum of 60 holding registers to be stored. The MM3 Motor Manager 3
response to this function code is to echo the slave address, function code, starting address,
the number of Setpoints stored, and the CRC.
For example, consider a request for slave 17 to store the value 01F4 to setpoint address
1028 and the value 2710 to setpoint address 1029.
The master/slave packets have the following format:
Master Transmission
Slave address
Function code
Data starting address
Number of setpoints
Byte count
Data word 1
Data word 2
CRC
Slave Response
Slave address
Function code
Data starting address
CHAPTER 8: COMMUNICATIONS
Bytes Example
1 11 message for slave 17
1 08 loopback test
2 00 00 must be 0000h
2 00 00 must be 0000h
2 E0 0B computed CRC error code
Bytes Example
1 11 message from slave 17
1 08 loopback test
2 00 00 must be 0000h
2 00 00 must be 0000h
2 E0 0B computed CRC error code
Bytes Example
1 11 message for slave 17
1 10 store multiple setpoints
2 10 28 setpoint address 1028h
2 00 02 2 setpoints = 4 bytes total
1 04 4 bytes of data
2 01 F4 data for address 1028h
2 27 10 data for address 1029h
2 33 23 computed CRC error code
Bytes Example
1 11 message from slave 17
1 10 store multiple setpoints
2 10 28 setpoint address 1028h
MM3 MOTOR MANAGER 3 – INSTRUCTION MANUAL
Description
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Description
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