80
AFQm
Instruction Manual
8.2.- PROTOCOL
In the Modbus protocol, the AFQm uses the RTU (Remote Terminal Unit) mode.
The Modbus functions implemented in the device are as follows:
Functions 03 and 04: Reading of n Words (2 bytes).
8.2.1.- EXAMPLE OF MODBUS QUERY
Query: Value of the Load current of L1
Address Function
Initial
register
No. of
registers
CRC
0 A 03 92 0002 xxxx
Address: 0A, Peripheral number: 10 in decimal.
Function: 03, Read function.
Initial Register: 92, register from which to start reading.
No. of registers: 0002, number of registers to be read.
CRC: xxxx, CRC character.
Response:
Address Function No. of Bytes Register no. 1 Register no. 2 CRC
0 A 03 04 0000 00FA xxxx
Address: 0A, Responding peripheral number: 10 in decimal.
Function: 03, Read function.
No. of bytes: 04, No. of bytes received.
Register: 000000FA, value of load current L1, with 1 decimal: 0xFA = 25.0 A
CRC: xxxx, CRC character.
8.2.2.- MODBUS MAP
All Modbus map variables are in hexadecimal format.
For these variables, Functions 03 and 04 are implemented.
8.2.2.1.- Load Measurements
Table 25:Modbus memory map: Measurements with Load (Table 1).
Parameter L1 L2 L3 LN Units
Current with Load 93 - 92 95 - 94 97 - 96 99 - 98 [Hi] + [Low] A with 1 decimal
Active power with Load AD - AE AF - B0 B1 - B2 - kW with 2 decimal places and sign.
Reactive power with Load B3 - B4 B5 - B6 B7 - B8 - kVar with 2 decimal places and sign.
Apparent power with Load B9 - BA BB - BC BD - BE - kVA with 2 decimal places and sign.
cos ɸ with Load D1 D2 D3 - With 3 decimal
Current THD with Load 8C 8D 8E - % with 1 decimal
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