Weidmuller WI-I/O-9-U2: Wireless Mesh I/O & Gateway User Manual V1.2.2 - Manual (Page 74)

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Figure 56 - Modbus TCP Client Mapping
Local Register (Master)
– When the Function Code (Command) is ‘Read’ the ‘Local
Register ’ will be the destination register or output location on the Local device, when the
Function Code (Command) is a ‘Write’ the ‘Local Register’ will be the originating register
or input location on the local device.
I/O Count – The number of consecutive I/O values in the mapping
Function Code (Command Type) – The Function Code of the Modbus command
determines if the command is going to be
‘Read’ or ‘Write’ and what type of register is
going to be used. When entering a mapping you need to select ‘Read’ or ‘Write’ from
the drop down
‘Command Type’ list then select one of the four radio buttons that
represent the different register types. Selecting the register type will change the
Destination (Slave) register address range to suit.
Destination Register (Slave)
– This is the register location on the TCP Server / RTU
Slave device and depending on what type of Modbus Command will only allow the
appropriate register to be selected.
Device ID
– The unit address (Device ID) of the Modbus TCP Server or Modbus RTU
Slave.
Server IP Address (Network Address - TCP Client only)
– The IP Address of the
Modbus TCP Server.
Server Port (TCP Client only) – The server port of the Slave device, Modbus TCP will
usually be the standard port address
of ‘502’.
Serial Port (Modbus RTU only)
– This is the Serial port used to connect to the device.
Select the port from the drop down list.
Response Time – This is the time waited for a response from a TCP Server or an RTU
Slave device before registering a Communications Fail.
Fail Reg
– The Comms Fail indication Register can be a physical output, i.e. DIO #1-8
(Reg 1-8) which will turn on a digital output when in fail. It can also be configured as an
internal holding register (Reg 30501) which will show the fail indication as well as any
Modbus Error Codes. Useful for diagnosing communication problems. See Appendix D:
‘for descriptions of these error codes.