Category Archives: PLC Communication

PLC communication protocol guides for industrial engineers.

Modbus TCP on the Siemens S7-1500 (TIA Portal): MB_CLIENT and MB_SERVER

The S7-1500 talks Modbus TCP straight out of its PROFINET port. No CP module, no license, no third-party library. You drop in two instructions — MB_CLIENT and MB_SERVER — point them at a connection structure, and you have a working Modbus link. That said, the part that trips people up isn’t dropping the block in. It’s the connection… Read More: Modbus TCP on the Siemens S7-1500 (TIA Portal): MB_CLIENT and… »

EtherCAT Protocol Explained: The Trick That Makes It Fast

EtherCAT is the protocol you reach for when 1 ms 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… Read More: EtherCAT Protocol Explained: The Trick That Makes It Fast »

Modbus TCP Mitsubishi iQ-R: Step-by-Step Setup (GX Works3, RJ71EN71, RnENCPU)

A practical engineering guide to configure Modbus TCP on the Mitsubishi MELSEC iQ-R series — quick setup, GX Works3 parameters, MODBUS Device Assignment, function codes, exception codes, float/endian handling, polling timing, and field troubleshooting Quick Setup (5 Steps) If you just need it working fast, here’s the short path: Step Action 1 GX Works3 → Module Parameter →… Read More: Modbus TCP Mitsubishi iQ-R: Step-by-Step Setup (GX Works3, RJ71EN71, RnENCPU) »

How to Configure Modbus TCP on Schneider M340 (Unity Pro / EcoStruxure Control Expert)

The Schneider Modicon M340 PLC is one of the most widely deployed PLCs in Europe, the Middle East, and Africa for water treatment, building automation, energy management, and machine control. Modbus TCP is its default Ethernet protocol — the embedded CPU Ethernet port is a Modbus TCP server out of the box. This guide shows you how to… Read More: How to Configure Modbus TCP on Schneider M340 (Unity Pro… »

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: How to Configure Modbus TCP on Allen-Bradley CompactLogix (Studio 5000… »

How to Configure Modbus TCP on Siemens S7-1200 (TIA Portal Step-by-Step)

The Siemens S7-1200 has built-in Modbus TCP support. No additional communication modules are needed. The CPU handles Modbus TCP natively through its PROFINET Ethernet port. You configure it using two instruction blocks in TIA Portal: A single S7-1200 can run both roles at the same time — serving data to SCADA while polling field devices. Despite the simplicity,… Read More: How to Configure Modbus TCP on Siemens S7-1200 (TIA Portal… »