Function Code 07H - GE Multilin MM200 Communications Manual

CHAPTER 2: RS485 INTERFACE (MODBUS RTU)

Function Code 07H

MM200 MOTOR MANAGEMENT SYSTEM – COMMUNICATIONS GUIDE
MASTER TRANSMISSION
DATA STARTING ADDRESS
DATA
CRC
SLAVE RESPONSE
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
DATA
CRC
Modbus Implementation: Read Exception Status
MM200 Implementation: Read Device Status
This is a function used to quickly read the status of a selected device. A short message
length allows for rapid reading of status. The status byte returned will have individual bits
set to 1 or 0 depending on the status of the slave device. For this example, consider the
following MM200 general status byte:
The master/slave packets have the following format:
Table 2-5: Function code 7 bitmask
Bit
0
1
2
3
4
5
6
7
Table 2-6: MASTER/SLAVE PACKET FORMAT FOR FUNCTION CODE 07H
MASTER TRANSMISSION
SLAVE ADDRESS
FUNCTION CODE
CRC
SLAVE RESPONSE
SLAVE ADDRESS
BYTES EXAMPLE
2 04 5C
2 00 02
2 CB B9
BYTES EXAMPLE
1 11
1 06
2 04 5C
2 00 02
2 CB B9
Function
Alarm
Trip
Internal fault
Auto
Contactor A
Contactor B
Contact output 3
Drive available (communications control)
BYTES EXAMPLE
1 11
1 07
2 4C 22
BYTES EXAMPLE
1 11
MODBUS FUNCTIONS
DESCRIPTION
setpoint address 04
5C
data for setpoint
address 04 5C
CRC error code
DESCRIPTION
message from slave
17
store single setpoint
setpoint address 04
5C
data stored in
setpoint address 04
5C
CRC error code
DESCRIPTION
message for slave 17
read device status
CRC error code
DESCRIPTION
message from slave
17
2-7