Remote Modbus Polling with Fernhill SCADA & Valtoris Gateways

1. Valtoris Gateway: 4G Network & Port Forwarding

To allow Fernhill SCADA to poll our remote devices over a cellular network, we first need to verify the connection and expose the local Modbus port via Port Forwarding.

Step 1.1: Verify 4G Cellular Connection

Navigate to Network -> 4G Network in the Valtoris Web GUI. Ensure the WAN mode is set to 4G Mode.

Fig 1. Verifying active 4G network connection.

Step 1.2: Configure Port Forwarding

Navigate to Network -> Firewall -> Port Forwards. We will create a rule to map incoming SCADA traffic to our internal PLC.

• External Port: 5020 (The port Fernhill SCADA will connect to)
• Internal IP Address: 192.168.1.100 (The local IP of your Modbus device)
• Internal Port: 502 (Standard Modbus TCP port)

Fig 2. Mapping External Port 5020 to Internal IP 192.168.1.100:502.

2. Fernhill SCADA: Data Reception & Configuration

With the hardware tunnel established, we configure the software side. Please ensure you have downloaded and installed the Fernhill SCADA Windows Developer package from their official website.

Step 2.1: Create a Working Folder

It is good practice to create a working folder for related tags.

• Connect the Fernhill SCADA Configuration Tool to a Fernhill SCADA Server.
• Right-click the database root folder and select Add new Folder.
• Change the name to ‘Valtoris’ and press RETURN.

Step 2.2: Create a Modbus TCP Channel Tag

• Right-click the folder you created in step 2.1.
• Select Add New Tag -> Modbus -> Modbus TCP/IP Channel.
• Change the name to ‘Channel’ and press RETURN.
• In the Properties Window: Set Port to 5020 (matching the External Port created in Step 1.2).
• Set Host to the IP Address of the Valtoris Gateway.
• In the Tag Status Window, check there is a successful connection.

Fig 3. Creating the Channel and setting the Fernhill Host IP/Port. Notice the ‘Online’ status in the Tag Status View confirming successful communication.

Step 2.3: Create a Modbus Device Tag

• Right-click the folder you created in step 2.1.
• Select Add New Tag -> Modbus -> Modbus Device.
• Press RETURN to accept the default name.
• In the Properties Window: Click the Browse “…” button of the Channel property.
• Select the Channel Tag you created in step 2.2. Click OK.
• Use the Tag Status Window to confirm the Modbus Device tag is working as expected.

Fig 4. Linking the new Modbus Device Tag to the previously created TCP/IP Channel.

Step 2.4: Create an Analog Data Point Tag

• Right-click the folder you created in step 2.1.
• Select Add New Tag -> Core -> I/O Analog Tag.
• Press RETURN to accept the default name.
• In the Properties Window: Click the Browse “…” button of the IODataSource property.
• Select the Modbus Device Tag you created in step 2.3. Click OK.
• In the IOItemName property, enter the Modbus Register Address. For example: 40001.
• Use the Tag Status Window to confirm the Analog Data Point Tag is working as expected.

Fig 5. Mapping the specific Modbus Register (40001) to a Fernhill SCADA Analog Data Point Tag. The Status View shows ‘Quality: 192 (Good)’, verifying data is being polled successfully.