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8 COMMUNICATIONS
1. First, preload the addresses listed in the first column of the table to in User Map Addresses #1 to #6
(addresses 0180 to 0185 hex).
Master Query Message:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS: high order byte
DATA STARTING ADDRESS: low order byte
NUMBER OF SETPOINTS: high order byte
NUMBER OF SETPOINTS: low order byte
BYTE COUNT
DATA #1: high order byte
DATA #1: low order byte
DATA #2: high order byte
DATA #2: low order byte
DATA #3: high order byte
DATA #3: low order byte
DATA #4: high order byte
DATA #4: low order byte
DATA #5: high order byte
DATA #5: low order byte
DATA #6: high order byte
DATA #6: low order byte
CRC: low order byte
CRC: high order byte
Field:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS: high order byte
DATA STARTING ADDRESS: low order byte
NUMBER OF SETPOINTS: high order byte
NUMBER OF SETPOINTS: low order byte
CRC: low order byte
CRC: high order byte
2. Now that the User Map Addresses have been setup, the required memory map locations can be accessed
via the User Map Values #1 to #6 (addresses 0100 to 0105 hex). Both actual values and setpoints may be
read.
Master Query Message:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS: high order byte
DATA STARTING ADDRESS: low order byte
NUMBER OF REGISTERS: high order byte
NUMBER OF REGISTERS: low order byte
CRC: low order byte
CRC: high order byte
GE Power Management
Example (hex):
11
query message for slave 11
10
store multiple setpoint values
01
data starting at address 0180
80
00
6 setpoint values = 12 bytes total
06
0C
12 bytes of data
0200 → Relay Status
02
00
0210 → W3 Phase Time O/C Flag
02
10
0300 → W1 Phase A 4th Harmonic Content
03
00
0301 → W1 Phase B 4th Harmonic Content
03
01
0302 → W1 Phase C 4th Harmonic Content
03
02
2002 → Percent Differential Pickup
20
02
2F
8A
Example (hex):
11
response message from slave 11
10
store multiple setpoint values
11
data starting at address 0180
80
00
6 setpoint values = 12 bytes total
06
42
8F
Example (hex):
11
query message for slave 11
03
read register values
01
data starting at address 0100
00
00
6 setpoint values = 12 bytes total
06
C6
A4
745 Transformer Management Relay
8.2 MODBUS PROTOCOL
8-13
8
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