3 modbus protocol specifications, 3 modbus protocol specifications -3, App index – Yokogawa Value Series FX1000 User Manual
Page 177: Modbus client function
6-3
IM 04L21B01-17EN
Specifications
1
2
3
4
5
6
App
Index
6.3 Modbus Protocol Specifications
Modbus Client Function
Basic Operation
• The FX, as a Modbus client device, communicates with Modbus servers periodically
by sending commands at specified intervals.
• The Modbus client function operates independently from the Modbus master function
via the serial communication.
• The supported functions are “reading data from the input registers and hold registers
on the server” and “writing data into the hold registers on the server.”
Modbus Client Specifications
Communicate via ModbusTCP
Communication media: Ethernet 10Base-T
Read cycle:
Select from the following:
1 s, 2 s, 5 s, and 10 s
Connection retry:
Select the reconnection interval after disconnecting the
connection after the connection wait time has elapsed from the
following:
OFF, 10 s, 20 s, 30 s, 1 min, 2 min, 5 min, 10 min, 20 min, 30
min, and 1 h
Connection timeout value: 1 min
However, when the IP address is not established with DHCP, a
communication error results immediately.
Command timeout value: 10 s
Server:
Set up to 16 servers
Supported functions:
Supported Modbus client functions are as follows:
The server device must support these functions.
Function Code
Function
Operation
3
Read the hold register
(4XXXX, 4XXXXX)
The FX reads the hold register of the server
device into the communication input data.
4
Read the input register
(3XXXX, 3XXXXX)
The FX reads the input register of the server
device into the communication input data.
16
Write to the hold register
(4XXXX, 4XXXXX)
The FX writes the measured or computed data to
the hold register of the server device.