XYR301E Wireless Ethernet
User Manual
Page 52
April 2012
Modbus TCP Client (Master) enables the XYR301-E to connect to one or more Modbus TCP Servers (Slaves).
All Modbus Master messages are directed to/from the onboard I/O registers depending on configuration (described
below). The Modbus TCP Client may also poll Modbus RTU (i.e. serial) devices connected to either the local serial
port or a remote XYR301-E serial port by enabling the Modbus TCP to RTU gateway at the corresponding serial port
(see section 3.10 “
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”).
Modbus TCP Client functionality allows a maximum of 100 mappings to be configured and a maximum of 25 different
Modbus TCP Servers.
Modbus TCP Server (Slave) enables the XYR301-E to accept connections
from one or more Modbus TCP Clients (Masters). All Modbus
transactions routed to the onboard Modbus TCP Server are directed
to/from the onboard general purpose I/O registers. The Modbus TCP
Server is shared with the Modbus TCP to RTU Gateway, so that the
Modbus “Device ID” is used to determine if a Modbus transaction is to be
routed to the onboard Modbus TCP Server or to a Modbus RTU device
connected to the serial port. Care should therefore be taken that all serially
connected Modbus devices use a different Modbus Device ID (i.e.
Modbus Slave Address) to the onboard Modbus TCP Server. Up to 32
separate connections to the Modbus TCP Server are supported.
Modbus RTU (serial) Master functionality is achieved by combining the Modbus TCP Client (Master) and Modbus
TCP to RTU Gateway. Simply specify a Modbus TCP Client (Master) connection to a Modbus TCP Server where the
server is the address of any XYR301-E with Modbus TCP to RTU Gateway enabled. Care should be taken to ensure
that the Device ID (i.e. Modbus Address) of the serial device is different to the Device ID of the onboard Modbus TCP
Server of the XYR301-E that the serial device is connected to.
The XYR301-E provides a configurable option to automatically reset the value of the onboard I/O registers to zero in
the event of a communications failure. If a valid Modbus transaction directed to/from a given register has not been
completed for longer than a configurable timeout, then the value of that register will be reset to zero.
An example of the Modbus functionality of the XYR301-E is illustrated below. In this example the status of the
onboard digital input at C will be reflected at the onboard digital output at B. Also, 8 single bit registers from Modbus
serial device D will be transferred to A.
Modbus RTU
Slave
Device
ID #5
Modbus TCP
Server
192.168.0.200
192.168.0.123
A
B C
D
Device
ID #1
Device
ID #6
Modbus RTU
Slave
Modbus TCP
Client
Содержание XYR301E
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