Function Code 07 - Read Device Status - GE Power Quality Meter Series Instruction Manual

7.2 MODBUS FUNCTIONS
Modbus Implementation: Read Exception Status
PQM 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.
PQM General Status Byte:
LSBit B0: Alarm condition = 1
B1: Self test failure = 1
B2: Alarm relay energized = 1
B3: Aux 1 relay energized = 1
B4: Aux 2 relay energized = 1
B5: Aux 3 relay energized = 1
B6: Not used
MSBit B7: Not used
MESSAGE FORMAT AND EXAMPLE:
Request status from slave 11.
Table 7–5: MASTER/SLAVE PACKET FORMAT FOR FUNCTION CODE 07H
MASTER TRANSMISSION
SLAVE ADDRESS
FUNCTION CODE
CRC
SLAVE RESPONSE
SLAVE ADDRESS
FUNCTION CODE
DEVICE STATUS (see definition above)
7
CRC
7-8
7.2.6 FUNCTION CODE 07 – READ DEVICE STATUS
BYTES EXAMPLE
1 11
1 07
2 4C 22
BYTES EXAMPLE
1 11
1 07
1 2C
2 22 28
PQM Power Quality Meter
7 MODBUS COMMUNICATIONS
DESCRIPTION
message for slave 17
read device status
CRC error code
DESCRIPTION
message from slave 17
read device status
status = 00101100 (in binary)
CRC error code
GE Power Management