Elpro Technologies 450U-E Wireless Ethernet Modem & Device Server User Manual
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www.cooperbussmann.com/wirelessresources
Rev Version 1.0.12-Beta7
Modbus
3.15
The 450U-E has an on-board Modbus TCP Server/RTU Slave and a Modbus TCP Client/RTU Master which provide
connectivity for a range of Modbus applications. The modem can be configured with any combination of the following
modes.
Modbus TCP Server This mode will allow an external Modbus TCP Client to access the internal I/O and status
registers of the module.
Modbus TCP Client This mode will allow the module to act as a TCP Client (Master) and poll external TCP
server devices, transferring any polled data values to either the internal registers or an external TCP server
device.
Modbus RTU Slave In this mode the module will act as a Modbus RTU slave and allow the internal registers to
be accessed by a Modbus RTU Master via the RS 232 or RS485 serial ports.
Modbus RTU Master This mode will allow the module to act as a Modbus RTU Master and poll any Modbus
RTU slave devices via the serial ports, transferring any data to or from the units internal I/O registers.
Modbus TCP to RTU Converter This mode will convert any Modbus TCP Client data coming in via the Radio
or Ethernet connections and pass it to any Modbus RTU devices connected to the serial ports and visa versa.
The Modbus TCP Client and the Modbus TCP Server/RTU Slave can be supported simultaneously, and when combined
with the built in Modbus TCP to RTU Gateway the 450U-E can transfer I/O to/from almost any combination of Modbus
TCP or RTU devices.
Modbus RTU Master ports
Each serial port has a number of parameters that can be adjusted for different applications.
TCP Port
Port numbers used for the Modbus TCP to RTU conversion Standard ports
are 503 for RS232 and 504 for RS485.
Pauses Between Requests
This is the delay between serial request retries in milliseconds
Response Timeout
The serial response timeout in milliseconds a serial retry will be sent if a
response is not received within this timeout. If using TCP to RTU
communication this Response time should be configured in conjunction with
the Response time for the TCP Client.
Connection Timeout
The TCP connection timeout in seconds if no Modbus/TCP data is received
within this timeout then the TCP connection will be dropped. Set this field to
zero for no timeout.
Maximum Request Retries
The maximum number of request retries performed serially.
Modbus TCP Server / RTU Slave
Modbus TCP Server / RTU Slave enable the 450U-E to accept connections from 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
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.
Figure 47 -Modbus TCP Server