EW50 Industrial LTE Cellular Gateway
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the Master and Slave sides.
However, if there is a network connection problem between the Modbus gateway and remote NOC/SCADA,
the remote Modbus server won’t be able to reach the Slave devices attached to the Modbus gateway, and
consequently, nothing can be monitored and stored under such situation.
With the Proxy mode option enabled, when the Modbus gateway loses the connection with specified Modbus
server, it will take over the data acquisition task and keep collecting the required data from Slave devices
automatically. Once the connection is recovered, the Modbus gateway will stop the data log proxy function.
The remote Modbus server can continue its data acquisition process, and if required, the administrator can
also retrieve the stored data log files.
Under the Data Logging Proxy mode, user must create some data acquisition rules via “Proxy Mode Rule
Configuration” for the collecting of the Slave devices data by the Gateway. If the network connection to remote
SCADA is lost unexpectedly, the Data Logging Proxy function will be triggered and begin to do the data polling
tasks by these pre-defined rules running in background.
Scenario for Sniffer Mode Data Logging
As Illustrated in the diagram, the Modbus gateway will store the following Modbus activities into a log file.
The Modbus request sent from Remote Modbus TCP Master.
The response (data) that is sent out from the polled Slave device (ID=3)