Connect to the network via WAN and LAN

The gateway has two network ports. Only the WAN port gives the gateway internet. Over the cable, it reads the Modbus devices more often than over 4G, from 1 second.

What you need

• A network cable to a router or switch on site that has internet.
• The gateway in the portal, added as described in Add a gateway.
• The role Owner, Admin or Technician to check the connection and to add a Modbus device.

Connect the WAN port to the site network

Plug a network cable from the router or switch on site into the WAN port. The gateway requests an IP address by itself through DHCP, so you set nothing on the gateway.

If the network has internet, the gateway sends its data over the cable.

Check the connection over the cable

The portal shows whether the gateway sends over the cable or over the SIM.

1. Open the gateway list

   Open Gateways in the menu. If the gateway shows Online, it reaches the portal.

2. Open the gateway

   Click the gateway.

3. Open the settings

   Click the pencil at the top right (Gateway settings).

4. Read the connection

   In the block Uitlezen via de SIM (reading via the SIM), look at Verstuurt nu via (sending now via). If it shows Kabel (cable), the gateway sends over the site network.

If it shows SIM while the cable is in the WAN port, the gateway sees no internet over the cable. What the firewall must allow is described in Network requirements for the gateway. If the gateway stays on Pending, see Gateway does not come online.

Connect a Modbus TCP device to the LAN port

On the LAN port, you connect a Modbus TCP device directly to the gateway. The Modbus TCP device gets no internet and no connection to the site network through the gateway.

The Modbus TCP device needs a fixed IP address in the address range of the LAN port. That address range is not shown in the portal.

1. Request the address range

   Request the address range of the LAN port through the support page. Include the serial number of the gateway.

2. Set the IP address

   On the Modbus TCP device, set a fixed IP address within that range.

3. Connect the cable

   Plug a network cable from the Modbus TCP device into the LAN port of the gateway.

4. Add the Modbus device

   Add the Modbus device with Modbus TCP and the fixed IP address, as described in Set the address and connection of a Modbus device.

Read a Modbus TCP device on the site network

If the Modbus TCP device is already on the site network, you need no extra cable. If it is in the same subnet as the WAN port, the gateway reads it through that port. Give the Modbus TCP device a fixed IP address, because the gateway always reads it at the IP address that is in the portal.

Poort (port) is set to 502 by default. If the Modbus TCP device uses another port, enter that port. Every Modbus TCP device needs its own unit ID per gateway, even if it has a different IP address. It must also not be the same as a slave address on the RS485 bus. How to enter these values is described in Set the address and connection of a Modbus device.

Automatic search scans the network on the WAN side only if the gateway sends over the cable. It searches only on port 502 and never outside the /24 around the gateway's own address. You add a Modbus TCP device on another port yourself. How the search works is described in Find Modbus devices with automatic search.

What the IT department needs to know

The gateway builds an outgoing connection to ModbusCloud by itself, using MQTT over TLS to port 8883. Port forwarding and a fixed public IP address are not needed. All ports and protocols that the firewall must allow are described in Network requirements for the gateway.

Without a network cable, over 4G

If there is no cable in the WAN port, or the network has no internet, the gateway sends through the backup SIM. As soon as the cable has internet again, it returns to the cable by itself.

Over the SIM, the gateway reads no more often than the SIM interval, 300 seconds (5 minutes) by default. That also applies to a Modbus TCP device on the LAN port. More about the SIM is described in 4G and the backup SIM.