7-8
PQM Power Quality Meter
GE Power Management
7.2 MODBUS FUNCTIONS
7 MODBUS COMMUNICATIONS
7
7.2.6 FUNCTION CODE 07 – READ DEVICE STATUS
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
BYTES
EXAMPLE
DESCRIPTION
SLAVE ADDRESS
1
11
message for slave 17
FUNCTION CODE
1
07
read device status
CRC
2
4C 22
CRC error code
SLAVE RESPONSE
BYTES
EXAMPLE
DESCRIPTION
SLAVE ADDRESS
1
11
message from slave 17
FUNCTION CODE
1
07
read device status
DEVICE STATUS (see definition above)
1
2C
status = 00101100 (in binary)
CRC
2
22 28
CRC error code
Summary of Contents for Power Quality Meter Series
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Page 46: ...2 22 PQM Power Quality Meter GE Power Management 2 2 ELECTRICAL 2 INSTALLATION 2 ...
Page 56: ...3 10 PQM Power Quality Meter GE Power Management 3 4 DEFAULT MESSAGES 3 OPERATION 3 ...
Page 166: ...6 20 PQM Power Quality Meter GE Power Management 6 6 POWER ANALYSIS 6 SOFTWARE 6 ...
Page 274: ...B 4 PQM Power Quality Meter GE Power Management B 1 TABLES AND FIGURES APPENDIXB B ...
Page 276: ...C 2 PQM Power Quality Meter GE Power Management C 1 PQM WARRANTY APPENDIXC C ...
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