8�2�- Modbus Protocol; 8�2�1�- Reading Example: Function 0X04; 8�2�2�- Writing Example: Function 0X05 - Circutor CVM-C11 Instruction Manual

8�2�- MODBUS PROTOCOL
In the Modbus protocol, the CVM-C11 device uses the RTU (Remote Terminal Unit) mode.
The Modbus functions implemented in the device are as follows:
Function 0x01: Reading a relay.
Function 0x02: Reading a digital input.
Function 0x03 and 0x04: Reading integer logs.
Function 0x05: Writing a relay.
Function 0x10: Writing multiple logs.
8�2�1�- READING EXAMPLE: FUNCTION 0x04�
Question: Instantaneous value of the phase voltage of L1
Address: 0A, Peripheral number: 10 in decimals.
Function: 04, Read function.
Initial Register: 0000, on which the reading will start.
No� of Registers: 0002, number of registers read.
CRC: 70B0, CRC Character.
Response:
Address: 0A, Responding peripheral number: 10 in decimals.
Function: 04, Read function.
No� of bytes: 04, No. of bytes received.
Registers: 0000084D, value of the phase voltage of L1: VL1 x 10 : 212.5V
CRC: 8621, CRC Character.
Note: Every Modbus frame has a maximum limit of 20 variables (40 logs).
8�2�2�- WRITING EXAMPLE: FUNCTION 0x05�
Question: Deleting maximum and minimum values.
Address: 0A, Peripheral number: 10 in decimal.
Function: 05, Read function.
Initial Register: 0834, Register of the parameter for deleting maximum and minimum values.
Value: FF00, we indicate that we want to delete the maximum and minimum values.
100
Address Function
0A 04
Address Function No� of Bytes
0A 04
Address Function
0A 05
Initial No� of
Register Registers
0000 0002
Register
Register No� 1
04 0000
Initial
Value
Register
0834 FF00
CRC
70B0
CRC
No� 2
084D 8621
CRC
CEEF
Instruction Manual
CVM-C11