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How to connect via proxy

Create new solution in Merbon IDE, assign a PLC and download the configuration. In the PLC properties, we check the network connection IP address, network mask, default gateway and DNS. In the proxy parameters (Network settings – Proxy parameters) we insert the Proxy ID, URL and Keep-alive Interval, which determines how often the PLC will report to the server. Finally, we enable Proxy.

  • New proxy ID - unencrypted communication http://proxy.merbon.cz:12349
  • New proxy ID - encrypted communication https://proxy.merbon.cz:12359
  • Old proxy ID starting with PRX2C - unencrypted communication http://proxy.mervis.info:6677
  • Old proxy ID starting with PRX2C - encrypted communication https://proxy.mervis.info:6678

  

Upload the configuration to the PLC.

Restart the PLC.

After restarting the PLC, upload the project to the PLC and start debugging. In the system status, you will see the status of the proxy server, the number of free slots and the number of occupied slots.

Proxy statuses:

  • Disabled – switched off (the configuration has not been uploaded into the PLC, or the INIT switch is on).
  • Connected – PLC successfully connected to the Proxy server, and a client (Merbon IDE / Merbon Visual / SCADA) is currently connected.
  • Connecting – please wait a moment.
  • Idle – PLC successfully connected to the Proxy server, no client is currently connected.
  • FailedToConnect – connection error, check URL syntax, TCP port and Proxy ID.
  • HostNotFound – server not found, check proxy server name, DNS server IP address and default gateway settings.
  • NotAvailable – unknown ID, check you server settings. Are you trying to connect to new server with old ID or to old server with new ID?
  • NotUsed – check your keep-alive interval, it should be 10s.

How to connect via proxy

End debugging mode. If you want to use profiles switch you solution to full mode. Create a derived profile from the profile in use. Switch to the derived profile, edit the Parameters for the connection with the PLC -> change the connection type to Proxy. Add the URI and Proxy ID to the connection parameters. Compile the assembly and start debugging.

  • New proxy ID - unencrypted communication proxy.merbon.cz:12348
  • New proxy ID - encrypted communication tcps://proxy.merbon.cz:12358
  • Old proxy ID starting with PRX2C - unencrypted communication proxy.mervis.info:12348
  • Old proxy ID starting with PRX2C - encrypted communication tcps://proxy.mervis.info:12349

 

In the system status is the connection status and you can see that one slot is occupied. All data from the controller is now available in the same way as if we were connected directly to the IP address of the PLC.

Proxy via mobile

If you want to use a proxy connection also in the Merbon Visual mobile application, create a new terminal, e.g. of type External rev. 2.2. Assign a template to it and add a PLC to its terminalChannel.

 

Select the Custom endpoint and set it according to the picture.

  • New proxy ID - unencrypted communication proxy.merbon.cz:12348
  • Old proxy ID starting with PRX2C - unencrypted communication proxy.mervis.info:12348

Now you can compile the terminal, right-click on it and select export definition, then send the resulting zip file to the mobile and open it in Merbon Visual. The mobile application does not support encrypted transmission, therefore the PLC will be set with port 12349 (or 6677 in case of old proxy ID) and the client with port 12348. If we use the user profile in the application, it is necessary to enter the translated address 81.31.38.186 instead of proxy.merbon.cz, or 77.240.189.136 instead of proxy.mervis.info if you are using an old proxy ID starting with PRX2C.

Responsive Settings

The default timeout setting for the HT200 terminal or mobile application is 30s. However, if you are connecting to multiple plcs via proxy at the same time, this may not be enough. It is good to raise the timeout to 60-120s according to the number of plcs (this can be found either in the mobile application or in the web settings of the HT200 terminal)