[willglynn]

Seconding Beckhoff. EtherCAT is a fantastic protocol, TwinCAT/BSD works great, reliability is excellent. It's super nice to run realtime PLC code on specific processor cores with µs of jitter while other cores run a normal OS with normal applications (e.g. VictoriaMetrics) on the controller itself.

I have a construction project involving several buildings with overlapping infrastructure. Everything gets connected to EtherCAT as quickly as possible. Electric generation: solar panels, batteries, inverters. Energy management: branch circuit monitoring, weather forecasts, solar forecasts, load control for things like EV charging and water heating. HVAC: heat pumps, buffer tanks, circulation pumps, valves. Building automation: lighting, access control. I just add I/O wherever, connect over Ethernet, and glue all the signals together in software.

I wouldn't dare approach a project like this with Arduino.

[doobiedowner]

How is procurement process with Beckhoff? I am tempted to make the jump from mostly AB.

[willglynn]

It's… fine? Unlike certain other brands, I've encountered no network of frothing, territorial, gatekeeping dealers with Beckhoff. For my project, I reached out to [e-mail], got a rep, asked for a quote, and went from there.

Secondhand can be viable too. Some of my "jellybean" EtherCAT terminals came from eBay. I won't get help from Beckhoff if they break, but given that I already have replacements on hand, I'm really not worried about it.

Beckhoff also lets you download almost all the development tools, runtimes, and PLC libraries without paying. In their words:

> Trial licenses can be generated in the TwinCAT 3 development environment (XAE) for many TwinCAT 3 functions for a validity period of 7 days. This can be repeated any number of times. An internet connection is not required for this. In this way, these TwinCAT functions can be used simply and cost-effectively in laboratory operations, e.g. in the education sector.

This is obviously useful for development and experimentation. It can also be an escape hatch in production if you need to substitute controllers. Beckhoff wants you to pay for what you use, sure, but their licensing scheme goes out of its way to avoid kicking you when you're down.