47
Instruction Manual
RECmax-CVM
7�2�- MODBUS PROTOCOL
In the Modbus protocol, the
RECmax-CVM
uses the RTU (Remote Terminal Unit) mode�
The Modbus functions implemented in the device are as follows:
Functions 0x03 and 0x04
� Reading integer registers�
Function 0x05
� Writing a relay�
Function 0x10
� Writing multiple registers�
7�2�1� READ EXAMPLE: Function 0x04�
Query:
Instantaneous value of the L1 phase voltage
Address
Function
Initial
Register
No� of
registers
CRC
0 A
04
0000
0002
70B0
Address: 0A
, Peripheral number: 10 in decimal�
Function: 04
, Read function�
Initial Register: 0000
, register from which to start reading�
No� of Registers: 0002
, number of registers to be read�
CRC: 70B0
, CRC character�
Response:
Address
Function
No� of Bytes Register no� 1 Register No� 2
CRC
0 A
04
04
0000
084D
86B1
Address: 0A
, Responding peripheral number: 10 in decimal�
Function: 04
, Read function�
No� of bytes: 04
, No� of bytes received�
Register: 0000084D
, value of the L1 phase voltage: VL1 x 10 : 212�5V
CRC: 86B1
, CRC character�
Note:
Every Modbus frame has a maximum limit of 20 variables (40 registers).
7�2�2� WRITE EXAMPLE: Function 0x05�
Query:
Deletion of maximum and minimum values�
Address
Function
Initial
Register
Value
CRC
0 A
05
0834
FF00
CEEF
Address: 0A
, Peripheral number: 10 in decimal�
Function: 05
, Write function�
Initial Register: 0834
, Register of deletion of maximum and minimum values parameter�
Value: FF00
, We indicate that we want to delete the maximum and minimum values�
CRC: CEEF
, CRC character�
