Flow Control Flow control is used by some serial devices to regulate the flow of data by turning on/
off flags that are used to tell the connected serial devices to start or stop transmitting data. The RS-232
supports CTC/RTS hardware flow control.
Serial Gateway
Mode
•
Server
—When configured as a server, the modem will wait for a TCP connection
to be initiated by a remote client.
•
Client
—When configured as a client, the modem will automatically attempt
to connect to a specific remote server that matches the configured device IP
address and port
Character Timeout Enter the maximum delay (in msec) between receiving the last serial character on the
serial port and the radio transmitting the whole packet. Data will be sent when this
time is exceeded.
Packet Size The Maximum number of received bytes that will be buffered before the packet is
sent. Data will be sent when packet size is exceeded.
Listen Port Only available when
“Server” is selected as the Serial Gateway Mode. Enter a TCP
port number on which the server must listen for incoming connections. Default is 24.
Remote Device Port Only available when
“Client” is selected as the Serial Gateway Mode. Enter the TCP
port number configured on the Listen Port of the remote Server. Default will be 24
Remote Device IP
Address
Only available when
“Client” is selected in the Serial Gateway Mode. Enter the IP
address of the remote server you want to communicate with.
Save Changes Save changes to non-volatile memory.
Save Changes and
Activate
Save changes to non-volatile memory and activate the process.
Modbus TCP/RTU Converter
The Modbus TCP/RTU converter function of the WI-MOD-xxx-E-5W allows an Ethernet Modbus TCP client (master)
to communicate with a serial Modbus RTU slave. The WI-MOD-xxx-E-5W makes this possible by internally
performing the necessary protocol conversion. The conversion is always performed by the WI-MOD-xxx-E-5W that
is directly connected to the Modbus serial device. Only this module needs to have Modbus TCP/RTU Conversion
enabled.
Figure 39 demonstrates how a Modbus/TCP client (master) can connect to one or more Modbus RTU slave devices.
In this example the WI-MOD-xxx-E-5W access point is configured with the RS-232 serial port set for
“Modbus TCP/
RTU
Converter.” When configured with this Port Type, the module converts the Modbus/TCP query from the client
into a Modbus RTU frame and forwards it out the appropriate serial port to the slave device. When the serial device
responds the query is received on the serial port, it is then converted into a Modbus/TCP response and forwarded
via the network to the Modbus/TCP client.
The Modbus TCP/RTU Converter may be configured to operate on either the RS-232 or RS-485 port.
Figure 39 Modbus TCP/RTU Converter
