Ethernet/IP communications


Thread Starter


I would like my Laptop to talk with a ControlLogix via an Ethernet/IP card. In this case, the Laptop is standalone, not connecting to any network; so its IP address is, and subnet mask is also How can I set up the Ethernet/IP card IP address so that my Laptop can go online with ControlLogix via the Ethernet/IP card?

Please help me out ASAP.

First, you have to configure and assign your ControlLogix ethernet card (either 1756-ENBT or 1756-ENET) with IP address and subnet mask, for example IP address:, subnet mask: To configure it, the easiest way is using serial connection and RSLinx. Once you established serial connection between RSLinx and ControlLogix, you can access ethernet card
properties and change IP address and subnet mask from there.

Second, after you complete the ControlLogix ethernet card configuration successfully, you have to configure your laptop ethernet port (both IP address and subnet mask). Please note that the subnet mask for laptop and PLC must be the same and the IP address for laptop must be the same as ControlLogix ethernet card IP address except for the last part. For example: if you have assigned for PLC then IP address for laptop is 192.168.1.X with X varying from 0 to 255.
You'll need an application with an Ethernet/IP driver that supports ControlLogix.

Check out for ControlLogix compatible .NET component, ActiveX Control, and OPC Server.

All come with pre-built example applications that will have you communicating with your ControlLogix in seconds.

Alan Hartwell

First, you must know the IP address and subnet mask of the controller. You must set the IP address and submask of your laptop so that the subnet mask is identical, and the IP address is identical, except that it must be different in the position where the subnet mask is zero (and not the same as any other device on the network).

For example, if the PLC IP address is and subnet mask is, set the laptop IP address as and subnet mask as

To configure the laptop IP address, go to Control Panel, open Network Connections, right click on the LAN connection, and click Properties. Click on TCP/IP, then the Properties button. Pick "Use the following IP address" and fill in the blanks. You can ignore the gateway part.

Good luck.