Hello everyone,

I’ve been trying to learn more about communication systems used in industrial automation, particularly between PLCs, HMIs, and other field devices.

From what I understand, protocols like Modbus and Ethernet/IP are commonly used, but I’m curious about real-world experiences when it comes to reliability and troubleshooting.

What are some best practices you follow to ensure stable communication in your systems? For example, things related to network setup, wiring, or common mistakes to avoid.

I’d really appreciate any insights or lessons learned from actual projects.

Thank you.

 

Modbus is definitely the easiest of the bunch to use. Both Modbus RTU and Modbus TCP. It is a old protocol and does not support some of the new security requirements (which themselves are a big issue for automation professionals to setup).

Ethernet/IP and Profinet has its quirks. Generally devices and softwares are supposed to work with each other seamless when they have passed conformance testing but in our experience that is not the case. There is at times some tuning required to get a device to work with a different PLC. Still it is not bad for simple integration.

Overall when devices are setup, then they work well - we have seen high reliability operation with field devices. Setup is where it takes time. PLC are well documented so generally finding online help is easier. Instrument providers are scattered, some have very extensive helps, tutorials - most others (smaller ones in particular) lack in published online support pages. A lot of smaller instrument providers do not even support fieldbuses - I guess the cost of integrating the stack in their firmware is too high.