Elpro Technologies 450U-E Wireless Ethernet Modem & Device Server User Manual
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Rev Version 1.0.12-Beta7
Modbus TCP Client functionality allows a maximum of 100 mappings to be configured and a maximum of 24
different Modbus TCP Servers.
Modbus TCP Client Mappings:
Local Register
Enter the starting onboard I/O register number that the specified Modbus
Master transaction will transfer I/O to/from.
I/O Count
Specify the number of consecutive I/O register to be transferred for the
specified transaction.
Function Code
Specify the Modbus Function Code for the transaction.
Destination Register
Enter the starting I/O register number in the destination device that the
specified Modbus Master transaction will transfer I/O to/from.
Device ID
Enter the Modbus Device ID of the destination Modbus device
Server IP Address
Specify the IP Address of the destination Modbus TCP Server for the
specified transaction.
Sever Port
Server Port number used for Modbus TCP. Default/standard port number
is 502
Response Timeout
Enter the timeout (in milliseconds) to wait for a response to the specified
transaction. Response time should be configured in conjunction with the
Response time for the serial ports if utilising TCP to RTU communications.
Comm Fail Register
Enter the onboard I/O Register number to store the communication status
of the specified transaction. The Specified register will be set to 0 if
communications is successful, 0xFFFF if there is no connection to the
specified server, or 0xFFxx where xx is the Modbus Exception Code
RTU Master Mappings
As the module is also communicating with a Modbus RTU slave device (Device #5) it will need to have an RTU Master
Mapping configured.
The RTU Mapping is configured to read 8 x Discrete values starting at register 1 from a Modbus Slave Device ID
#5 connected to the RS485 port and store the values at its own local internal register.
Local Register
(501)
specifies a general purpose Bit Storage area in the module.
I/O Count
(8) specifies that it is passing 8 discrete
I/O points.
Function Code
02: Read Discretes specifies the standard Modbus function code to read discrete
(i.e. digital) inputs.
Destination Register
(1) specifies the register that will be read at the Modbus RTU Slave (unit
C).
Device ID (
3) is the ID of the onboard Modbus RTU Slave at C.
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 450U-E that the serial device is connected to.
When configuring RTU Master Mappings you will need to ensure the appropriate serial port is
configured for the right mode, in this case the port will need to be configured as a Modbus Master.
For more details on how this is done see section 3.11 Serial Port Configuration
Modbus RTU Master Mappings:
Figure 50 - Site B RTU Mapping
