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7.3 Correspondence between communication value and actual value
It is agreed that Val_t is the communication readout value and Val_s is the actual value.
7.3.1
Voltage, Current, Power Factor, Frequency, Unbalance (Secondary
The series of measured values are read with 03 command of the Modbus-RTU communication protocol. Each item occupies 1 word.
The correspondence between the communication value and the actual secondary measurement value is shown in the following table:
For example: To read phase A voltage Uan, the data can be read at address 243 in Int16eger reading mode by MODSCAN, the
communication read-out value Val_t is 2200,then Val_t = 2200*0.1=220V.
7.3.2
Voltage, Current, Power Factor, Frequency, Unbalance (Primary)
The series of measured values are read with 03 command of the Modbus-RTU communication protocol. The voltage and current
occupy 2 words, and the power factor, frequency, and unbalance occupy 1 byte. The correspondence between the communication value
and the actual secondary measurement value is shown in the following table:
For example: To read phase A voltage Uan, the data can be read at address 1120-1121 in Int16eger reading mode by
MODSCAN,the communication read-out value is 9 at address 1120, communication read-out value is 10176 at address 1121,that is,
communication read-out value Val_t is 9*65536+10176 = 600000, then Val_s = Val_t*0.1=600000*0.1=60kV.
7.3.3
Active power, reactive power, apparent power and energy (Secondary side; W/Var/VA/kWh)
The series of measured values are read with 03 command of the Modbus-RTU communication protocol. Each item occupies 1 word.
The power resolution 0.01, the correspondence between the communication value and the actual value is as follows: Val_s=Val_t*0.01;
The energy resolution is 1, and the correspondence between the communication value and the actual value is as follows: Val_s=Val_t*1;
where Val_t=first word×65536+second word.
For example: To read phase A active power Pa, the data can be read at address 253-254 in Int16eger reading mode by
Applicable parameters
Resolution
Correspondence
Unit
Voltage ,Uan
、
Ubn
、
Ucn
、
Uab
、
Ubc
、
Uca
0.1V
Val_s
＝
Val_t*0.1
V
Current ,I
A
、
I
B
、
I
C
0.001A
Val_s
＝
Val_t*0.001
A
Power factor, PF
A
、
PF
B
、
PF
C
、
PF
总
0.001
Val_s
＝
Val_t*0.001
No unit
Frequency, F
0.01Hz
Val_s
＝
Val_t*0.01
Hz
Unbalance ,I(ubl)
，
ULL(ubl),ULN(ubl)
0.1
Val_s
＝
Val_t*0.1
%
Applicable parameters
Resolution
Correspondence
Unit
Voltage,Uan
、
Ubn
、
Ucn
、
Uab
、
Ubc
、
Uca
0.1V
Val_s
＝
Val_t*0.1
V
Current ,I
A
、
I
B
、
I
C
0.001A
Val_s
＝
Val_t*0.001
A
Power factor, PF
A
、
PF
B
、
PF
C
、
PF
Total
0.001
Val_s
＝
Val_t*0.001
No unit
Frequency, F
0.01Hz
Val_s
＝
Val_t*0.01
Hz
Unbalance ,I(ubl)
，
ULL(ubl),ULN(ubl)
0.1
Val_s
＝
Val_t*0.1
%
