GE 469

18 469 MOTOR MANAGEMENT RELAY – COMMUNICATIONS GUIDE
MODBUS MEMORY MAP COMMUNICATIONS GUIDE
EXAMPLE CASES
Table 4: Example cases to demonstrate scaling factor in Phase current
Table 5: Example case to demonstrate scaling factor in Ground Current, CT type 1A
secondary or CT type 5A secondary.
Table 6: Example case to demonstrate scaling factor in Ground Current, Multilin CT
1 Phase B current 500 1 x CT CT primary /500 1180
2 Phase C current 500 1 x CT CT primary /500 1180
3 Differential phase A current 500 1 x CT Differential CT primary /500 1185
4 Differential phase B current 500 1 x CT Differential CT primary /500 1185
5 Differential phase C current 500 1 x CT Differential CT primary /500 1185
6 Ground current ,
CT type = 1A or 5A secondary
500 1 x CT Ground CT primary/500 1183
6 Ground current ,
CT type = Multlin CT 50/0.025
500 1 x CT 1 Ampere/500 1182
7 Phase A voltage 2500 1 x VT 120 V * ( Phase VT ratio)/2500 11A1
8 Phase B voltage 2500 1 x VT 120 V * ( Phase VT ratio)/2500 11A1
9 Phase C voltage 2500 1 x VT 120 V * ( Phase VT ratio)/2500 11A1
10 Relay output states N/A N/A N/A
Channel
Let A represent
Modbus value
At register 1180,
CT PRIMARY
Actual
Primary
Current
Value in waveform
capture trace data
register
3100 to 36FF
Scale factor
SF
current
= A / B
Ia 1500 A 1000 A 333 A/B = 3
Ia 1000 A 1000 A 500 A/B = 2
Ia 500 A 1000 A 1000 A/B = 1
Channel
Let A represent
Modbus value
At register 1183,
Ground CT PRIMARY
Actual
Primary
Current
Value in waveform
capture trace data
register
3100 to 36FF
Scale factor
SF
current
= A / B
Ig 10 A 10 A 500 A/B=0.02
Channel
Let A represent
Ground CT Type
Multilin.
Modbus register
1182 has value 3.
Actual
Primary
Current
Value in waveform
capture trace data
register
3100 to 36FF
Scale factor
SF
current
= A / B
Ig 1 A 1 A 500 A/B=0.002