Modbus Gateway Settings - VSCOM ModGate Plus User Manual

6 Modbus Configuration

6.3. Modbus Gateway Settings

As explained above (6) you have to select the mode of packet forwarding, i.e. the Mapping scheme.
On single port models Line Mapping is preselected.
ListenAddress Specifies the IP Address the modbus gateway application listens on. The default
value is 0.0.0.0, which means ModGate Plus accepts connections on all interfaces (Ethernet
and WLAN) in parallel. Enter the IP Address of either Ethernet or WLAN to restrict the
Gateway function to this interface.
ListenPort Specifies the TCP port number the Modbus gateway application listens on. The default
value is 502, which is the reserved port for Modbus/TCP protocol.
GatewayMode You have to specify the mode which the gateway operates in. DirectMappingMode
(Mapping of Modbus devices to serial ports or TCP connections) or LineMappingMode (Map-
ping of serial ports to TCP connections).
Allow unknown clients Enables all stations to connect to ModGate Plus without prior configura-
tion as an allowed source for data.
Verbose When enabled the Modbus gateway application writes more debug output in the logfile
(/var/log/modbusgw.log). Don't enable this, unless you want to resolve problems!
The combination of LineMappingMode with Allow unknown clients is most useful for single
port models. All requests from unknown masters on TCP is directed to the single or first serial
port.
LineMappingMode on multi-port models requires the definition of TCP connections. This allows
the assignment of certain clients (Modbus Master) on TCP to a distinct serial port.
The DirectMappingMode routes Modbus requests to the targets based on the Modbus ID from the
defined TCP Connections or Serial Ports. If Allow unknown clients is enabled the requests may
originate from any source, including unknown clients.
June 2018
Figure 22: Gateway Settings
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