HRX-OM-Y120
Chapter 5 Ethernet Modbus / TCP communication
HRL Series
5.10
Function codes
5-9
A) Transaction identifier
：
Transaction identifier (2byte)
Copy the server. In general, all values are set to 0.
B) Protocol identifier
：
All protocol identifiers
（
2byte
）
are set to 0.
C) Length field
：
Field length (2byte)
・
Upper byte
：
fixed to 0.
（
As all messages are 256byte or less
）
・
Lower byte
：
Indicate the number of bytes afterwards.
D) Unit identifier
：
Unit identifier (1byte)
This is equivalent to the existing Modbus communication remote address, but each device is
identified by the IP address.
E) Function
（
Refer to “5.10
）
Designate command.
F) Data
Specify the register address, quantity, reading and writing in accordance with Function.
In Modbus / TCP, checksum
（
CRC and LRC
）
field are not available. Data is checked by
TCP/IP and Ethernet processing data.
5.10 Function codes
Function codes for reading or writing the register are shown
below.Table 5.10-1
Refer to 5.11 Description of each function code for
details.
Table 5.10-1
Function codes
NO
Code
Name
Function
1
04(04h)
read input registers
Read multiple registers
2
06(06h)
preset single register
Writing registers
3
16(10h)
preset multiple registers Write multiple registers
