Weidmuller Wireless Ethernet Modem & Device Server WI-MOD-E-G/A User Manual
Rev.
2.16
www.weidmuller.com
46
Figure 36 - Modbus
4373
Serial Gateway Connection Status (RS485) inverted
4374
TCP-RTU Connection Status (RS232) inverted
4375
TCP-RTU Connection Status (RS485) inverted
4376
TCP-RTU Modbus Server Connection Status inverted
4377
Multicast Pipe Connection Status inverted
4378-4999
Reserved for future use
Modbus TCP Client (Master) enables the WI-MOD-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 WI-MOD-E serial port
by enabling the Modbus TCP to RTU gateway at the corresponding serial
port (see section 3.11 - ”Serial Port Configuration”.
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 WI-MOD-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 WI-MOD-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 WI-
MOD-E that the serial device is connected to.
The WI-MOD-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.
Figure 35 - Modbus TCP