Are questions on working with PLC programming software on-topic here?

Question

I am an industrial controls engineer. I work with PLC hardware and software.

I am wondering if questions about PLC programming software are on-topic here. For example, I was thinking about asking a question about determining which version of Rockwell Software is required to open a particular .ACD file, which is a project file for Rockwell/Allen-Bradley PLC. (I figured out the answer myself, so I would probably self-answer this question.)

The question isn't about programming, exactly, so I doubt it would be on-topic on Stack Overflow. It is definitely related to Electrical Engineering, although I rarely see any questions of this type on this site. The question certainly isn't hardware-related.

I personally would love to see these types of questions here, but I'm curious how the current users of the site feel about it.

If it would not be a good fit here, would it perhaps be more welcome at Engineering.SE? Does that site handle Electrical Engineering topics that are related to industrial controls?

Answer 1

I'm inclined to say that PLC software and programming is on-topic. (If you disagree, please feel free to downvote).

Please note, I have very limited experience with PLCs, I welcome concerns and comments from more experienced users.

The standard reasoning that we use for software and programming is that it's on-topic as long as it's not so removed from the hardware or programming environment that it's a better fit on StackOverflow. We allow questions on Quartus, Atmel Studio, and other development environments, and I don't see why we shouldn't allow the same for PLC development.

Answer 2

What W5VO said, but in addition, make sure you specify your environment properly. State what hardware you are using, what language, what compiler or software environment if it matters, etc. We get too many questions here like "How do I set a single register bit without affecting the other bits" without specifying the micro or the language. Those will get closed and downvoted to oblivion for good reason.

The reason you don't see a lot of PLC questions here is because we don't have a lot of PLC users here. I agree this is on-topic as long as there is a hardware-related angle. It's been my observation that in the real world, EEs don't do PLCs as much as "production engineers" or the like. In some sense, the PLC language is designed to appeal to those that would run away screaming if they realized they were programming a computer. It's basically programming for those that don't want to admit they're programming, with doesn't apply to most EEs (and shouldn't apply to any EE).

Answer 3

One thing worth note here is the many similarities between PLCs and PLDs/FPGAs. I don't think anyone would label the latter off-topic here, nor that anyone would label VHDL or Verilog off-topic for this site.

Historically, the first use of PLCs was to replace chains of relay logic. The first use of PLDs was to replace chains of digital logic. Then as the technologies evolved, both PLCs and PLDs got more functionality, more uses, more advanced languages and so on.

Both technologies are supposedly general-purpose, yet they are used in niche markets with specific needs: mainly factory automation in the case of PLCs, mainly telecommunications in the case of PLDs.

With this in mind, I don't quite see how it would make sense to label PLC programming as off-topic, where VHDL or Verilog programming is considered on-topic. They are both forms of niche programming of electronic devices.

Answer 4

I'm very much a n00b but it would seem to me PLCs both hardware and software should be on topic. At least here in the UK, PLCs are very much seen as within the remit of the electrician and electrical engineer rather than say in the "programmers' trade". If you see what I mean.