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9 MODBUS COMMUNICATIONS
9 MODBUS COMMUNICATIONS 9.1 IMPLEMENTATION
The SPM supports a subset of the AEG Modicon Modbus RTU serial communication standard using a 2-wire
RS485 interface. The following commands are supported (Modbus names are in brackets):
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03: Read Setpoints and Actual Values (read holding registers)
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04: Read Setpoints and Actual Values (read input registers)
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05: Execute Operation (force single coil; coil number 1 emulates the relay reset function)
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06: Store Single Setpoint (preset single register)
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07: Read Device Status (read exception status)
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16: Store Multiple Setpoints (preset multiple registers)
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Baud rates: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200.
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Turn around time less than 50 ms from receipt of last character to transmission of first character.
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Two-wire RS485 connection.
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Data frame fixed at 1 start, 8 data and 1 stop bit.
The following setpoints are required to set up the Modbus communications port:
CONFIGURATIONS \ RTU ADDRESS:Range 1 to 254. Set to the SPM address
CONFIGURATIONS \ BAUD RATE: Set from 300 to 115k baud
CONFIGURATIONS \ PARITY: Set to none, even or odd, depending on configuration
CONFIGURATIONS \ TURNAROUND: Enter the minimum Modbus turnaround time, 0 to 1000 ms
The following table lists the coil numbers, which may be used in the Modbus "force coil" command.
Table 9–1: EXECUTE OPERATION CODES
COIL NUMBER FUNCTION
0001h
Simulate a keypad reset (i.e., reset a trip after the condition has cleared)
0101h
Force the FAR into the energized state
0111h
Force the FAR into the de-energized state
0121h
Un-force the FAR, reverting it to program control
0102h
Force the FCX relay into the energized state
0112h
Force the FCX relay into the de-energized state
0122h
Un-force the FCX relay, reverting it to program control
0103h
Force the TRP relay into the energized state
0113h
Force the TRP relay into the de-energized state
0123h
Un-force the TRP relay, reverting it to program control
GE Multilin
Courtesy of store.ips.us
(must be unique for each relay on the channel).
9.1.4 EXECUTE OPERATION COMMAND CODES (COIL NUMBERS)
SPM Synchronous Motor Protection and Control
9.1 IMPLEMENTATION
9.1.1 MODBUS PROTOCOL
9.1.2 PERFORMANCE REQUIREMENTS
9.1.3 SETPOINTS
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