GE Power Management
469 Motor Management Relay
6-11
6 COMMUNICATIONS
6.2 SUPPORTED MODBUS FUNCTIONS
6
6.2.6 FUNCTION CODE 07: READ DEVICE STATUS
Modbus Implementation:
Read Exception Status
469 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.
469 General Status Byte:
If status is neither stopped or running, motor is starting.
MESSAGE FORMAT AND EXAMPLE
Request status from slave 11.
Bit No.
Description
B0
R1 Trip relay operated = 1
B1
R2 Auxiliary relay operated = 1
B2
R3 Auxiliary relay operated = 1
B3
R4 Alarm relay operated = 1
B4
R5 Block start relay operated = 1
B5
R6 Service relay operated = 1
B6
Stopped = 1
B7
Running = 1
MASTER TRANSMISSION:
BYTES
EXAMPLE / DESCRIPTION
SLAVE ADDRESS
1
0B
message for slave 11
FUNCTION CODE
1
07
read device status
CRC
2
47 42
CRC calculated by the master
SLAVE RESPONSE:
BYTES
EXAMPLE / DESCRIPTION
SLAVE ADDRESS
1
0B
response message from slave 11
FUNCTION CODE
1
07
read device status
DEVICE STATUS
1
59
status = 01011001 in binary
CRC
2
C2 08
CRC calculated by the slave
NOTE