Write Multiple Registers (Modbus Function Code 16 (0X10)); Request; Response - Xytronix Research & Design ControlByWeb X317 User Manual

Operation
5.3.5

Write Multiple Registers (Modbus Function Code 16 (0x10))

The Write Multiple Registers function is used to write (set) the analog output value(s).
32-bit values are written to 16-bit register pairs. Consequently, addresses and registers must be even
numbers.

5.3.5.1 Request

Modbus TCP Request Frame Example – Write Analog Channel(s)
Field Name
Transaction Identifier
Protocol Identifier
Message Length
Unit Identifier
Function Code
Start Address
Quantity of registers
Byte Count
Data

5.3.5.2 Response

Response Frame Example
Field Name
Transaction Identifier
Protocol Identifier
Message Length
Unit Identifier
Function Code
Starting Address
Quantity of registers
Page 48
Length Function
2 bytes Synchronization number.
2 bytes Zero for Modbus/TCP
2 bytes Number of bytes in frame (below)
1 byte Slave Address (0xff if not used)
1 byte Write multiple registers
2 bytes Start Address:
2 bytes Quantity of registers:
1 byte Byte count (2 x N)
N * 2 Register(s) value:
Length Function
2 bytes Synchronization number.
2 bytes Zero for Modbus/TCP
2 bytes Number of bytes in frame (below)
1 byte Slave Address (0xff if not used)
1 byte Write multiple registers
2-bytes Starting address
2-bytes Quantity of registers
X-317™ Users Manual
Example Data
(AnalogOut1)
0x0001
0x0000
0x000B
0xFF
0x10
0x0510
0x0002
0x02
0x800042A2
Example Data
0x0001
0x0000
0x0006
0xFF
0x10
0x0510
0x0002
Xytronix Research & Design, Inc.