Category Archives: PLC Communication

PLC communication protocol guides for industrial engineers.

How to Configure CIP (EtherNet/IP) on Allen-Bradley Controllers

On an Allen-Bradley controller, “CIP” and “EtherNet/IP” are the same conversation. CIP is the protocol — the object model, the services, the way data is named. EtherNet/IP is CIP running on top of standard Ethernet. When you configure a Rockwell PLC to talk to a drive, a remote I/O block, a camera, or another controller, you’re configuring EtherNet/IP,… Read More »

PROFINET vs EtherCAT: An Honest Comparison for Real Projects

Pick the wrong industrial Ethernet protocol for a new machine and you live with it for 15 years. Wrong drives. Wrong I/O. Wrong engineering tools. Wrong training. That is why the PROFINET vs EtherCAT question — sometimes asked as EtherCAT vs PROFINET — matters more than the spec sheet suggests. Both protocols are real-time Ethernet standards, both are… Read More »

EtherCAT Protocol Explained: The Trick That Makes It Fast

EtherCAT is the protocol you reach for when 1ms is too slow. Motion control, multi-axis robotics, high-speed test rigs, anything synchronized down to the microsecond — that is EtherCAT territory. It looks like Ethernet, runs on the same cables, uses standard RJ45 connectors. But under the hood it does something no other industrial Ethernet protocol does: it reads… Read More »

How to Configure Modbus TCP on Allen-Bradley CompactLogix (Studio 5000 Step-by-Step)

Allen-Bradley CompactLogix and ControlLogix PLCs do not support Modbus TCP natively. Their primary protocol is EtherNet/IP. But in many industrial systems, you need to communicate with Modbus TCP devices — energy meters, VFDs, third-party sensors, or legacy equipment. Rockwell Automation provides a free solution: Modbus TCP Add-On Instructions (AOIs). These are pre-built function blocks you import into Studio… Read More »