Weidmuller WI-I/O-9-U2: Wireless Mesh I/O & Gateway User Manual V1.2.2 - Manual (Page 70)

69
4.3.13 Serial Configuration
The WI-I/O 9-U2 has an RS-232, and an RS-485 port for serial communications.
These ports are used to connect WEIDMULLER WI-I/O-EX-1-S-11, WI-I/O-EX-1-S-12 &
WI-I/O-EX-1-S-13 serial expansion I/O modules.
The ports can also be used to connect external Modbus RTU Master or Slave devices
The port Operating Mode and the normal serial parameters, Baud Rate, Data Format,
Flow Control, etc. will all need to be selected from the drop down lists depending on
what sort of device is connected and how it is going to operate.
Note: An error indications will be displayed if the Operating Mode selection is
incompatible with the configuration, i.e. If Modbus mode is not selected when a
Modbus mappings are configured.
Each serial port can be configured to operate in one of 3 operating modes.
Modbus RTU Master – This mode should be configured when the port is operating as a
Modbus Master, i.e. if Modbus RTU slave devices are connected directly to the serial
port.
Modbus RTU Slave – This operating mode should be used if the port is being used as
a Modbus RTU slave, i.e. if a Modbus Master (DCS, Scada, etc.) is connected to the
serial port.
Expansion I/O
– This operating Mode should be selected when Weidmuller Serial
Expansion modules are connected to the module.
Modbus RTU Master
The Modbus RTU Master should be configured if
the WI-I/O 9-U2 is acting as a Modbus RTU Master
and polling Modbus Slave devices via the serial
port selected.
It will also allow Ethernet Modbus/TCP Clients
connected to the WI-I/O 9-U2 Ethernet port to
communicate with Modbus RTU Slave devices
connected to the configured serial port. The WI-I/O
9-U2 makes this possible by internally performing
the necessary protocol conversion. The conversion
is performed by the WI-I/O 9-U2, which is directly
connected to the Modbus serial device (i.e. only
this module needs to have Modbus TCP to RTU
Gateway enabled).
When configured as a Modbus RTU Master there are a number of parameters that can
be adjusted depending on the devices connected.
Port Number
– This is the Port number configured for the serial port. The default port
number for the RS232 port is 503 and 504 for the RS485. This means if a TCP Client
needs to communicate with a serial device connected to the RS232 port of the WI-I/O 9-
Figure 53 - Modbus TCP/RTU