7-10
745 Transformer Management Relay
GE Multilin
7.3 MODBUS FUNCTIONS
7 COMMUNICATIONS
7
For an example of how to use the User Map feature, say the master computer is required to continuously read the memory
map locations shown below from slave 11. Normally, this would require at least 4 separate master query messages.
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).
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.
ADDRESS
DESCRIPTION
TYPE
0200H
Relay Status
actual value
0210H
W3 Phase Time O/C Flag
actual value
0300H
W1 Phase A 4th Harmonic Content
actual value
0301H
W1 Phase B 4th Harmonic Content
actual value
0302 hex
W1 Phase C 4th Harmonic Content
actual value
2002 hex
Percent Differential Pickup
setpoint
MASTER QUERY MESSAGE:
EXAMPLE (HEX):
SLAVE ADDRESS
11
query message for slave 11
FUNCTION CODE
10
store multiple setpoint values
DATA STARTING ADDRESS: high order byte, low order byte
01 80
data starting at address 0180
NUMBER OF SETPOINTS: high order byte, low order byte
00 06
6 setpoint values = 12 bytes total
BYTE COUNT
0C
12 bytes of data
DATA #1: high order byte, low order byte
02 00
0200
→
Relay Status
DATA #2: high order byte, low order byte
02 10
0210
→
W3 Phase Time O/C Flag
DATA #3: high order byte, low order byte
03 00
0300
→
W1 Phase A 4th Harmonic Content
DATA #4: high order byte, low order byte
03 01
0301
→
W1 Phase B 4th Harmonic Content
DATA #5: high order byte, low order byte
03 02
0302
→
W1 Phase C 4th Harmonic Content
DATA #6: high order byte, low order byte
20 02
2002
→
Percent Differential Pickup
CRC: low order byte, high order byte
2F 8A
CRC computed by master
SLAVE RESPONSE:
EXAMPLE (HEX):
SLAVE ADDRESS
11
response message from slave 11
FUNCTION CODE
10
store multiple setpoint values
DATA STARTING ADDRESS: high order byte, low order byte
11 80
data starting at address 0180
NUMBER OF SETPOINTS: high order byte, low order byte
00 06
6 setpoint values = 12 bytes total
CRC: low order byte, high order byte
42 8F
CRC computed by slave
MASTER QUERY MESSAGE:
EXAMPLE (HEX):
SLAVE ADDRESS
11
query message for slave 11
FUNCTION CODE
03
read register values
DATA STARTING ADDRESS: high order byte, low order byte
01 00
data starting at address 0100
NUMBER OF REGISTERS: high order byte, low order byte
00 06
6 setpoint values = 12 bytes total
CRC: low order byte, high order byte
C6 A4
CRC computed by master
SLAVE RESPONSE:
EXAMPLE (HEX):
SLAVE ADDRESS
11
response message from slave 11
FUNCTION CODE
03
read register values
BYTE COUNT
0C
6 registers values = 12 bytes of data
DATA #1: high order byte, low order byte
82 01
Relay Status
DATA #2: high order byte, low order byte
00 01
W3 Phase Time O/C Flag = not operated
DATA #3: high order byte, low order byte
00 01
W1 Phase A 4th Harmonic Content = 1%
ƒ
0
DATA #4: high order byte, low order byte
00 01
W1 Phase B 4th Harmonic Content = 1%
ƒ
0
DATA #5: high order byte, low order byte
00 01
W1 Phase C 4th Harmonic Content = 1%
ƒ
0
DATA #6: high order byte, low order byte
00 1E
Percent Differential Pickup = 0.30
×
I
d
CRC: low order byte, high order byte
80 F1
CRC computed by slave