As mentioned in the last section, we could program and manage our ControlLogix program using a serial cable connection; however, having an IP-based connection is much more practical. In most cases, a ControlLogix EtherNet/IP card is required for us to connect to our controller using an Ethernet connection. Although it is possible to purchase L8 CPUs that have an integrated Ethernet connection, it is much cheaper to purchase a used CPU and an EtherNet/IP card separately. With that being said, when you are buying a new ControlLogix CPU, it is cheaper to buy the L8 than an L7 and an EtherNet/IP card separately.
The following is a photo of the EtherNet/IP card that I will be using for the Robot Bartender project:
I will be using the 1756-ENBT/EtherNet/IP module, although any 1756 Ethernet communication modules will suffice. Now that we have our power supply, rack, CPU, and network connectivity sorted...