Control Panel designing

C

Thread Starter

Carlos Federico

Where can I learn how to design PLC Control Panels?

Is there any interesting Book?
 
B

Bob Peterson

Like many things in life there really are no effective short cuts to learning. You cannot learn to design PLC control panels from a book. nomatter what the books PR flacks might tell you.

While your somewhat tortured English suggests you are not US based, I will suggest some things that would apply in the US. The same kinds of things would apply to where ever you are, but you would need to substitute what applies locally.

First off, you will need a basic understanding of electricity and electronics. You do not need genius level type understanding, nor even be an engineer or have an engineering degree. It just is not necessary. You do need to understand the basics though. You need to know what diodes, transistors, triacs, relays, and other components are, and a good understanding of how they work. You need to have a basic understanding of how electricity works. What is voltage and current? What is resistance, capacitance, and inductance. Maybe something along the lines of a 2 year degree level.

You will need to understand at least something about what you are trying to control and how to apply and select them. Motor starters, VFDs, fuses, circuit breakers, and other panel based devices. You will also need to have a good understanding of how to use field devices like motors, solenoids, switches, transmitters and the whole gamut of other things that will need to hook to your I/O. Some of it is analog, some of it is digital. You can have voltages that are AC or DC and range from 5V to 600V. Sometimes even higher. Again, you do not need to have a high degree of knowledge here. Mostly you need to know enough to know when you run across something that you don't know, and that is very hard for the neophyte.

The PLC side of it is relatively easy. Usually, the brand and style of PLC is selected by someone else and you have to use what the PLC manufacturer has available. You match what you need to control with what the manufacturer has available and what the customer(s) want and/or will accept.

There are national and local standards that often have to be met such as UL508a, NFPA79, and the NEC. A lot of times those standards are not easy to understand or to follow because of the way they are written. I have been doing this for >30 years and just yesterday found myself writing an email questioning just what UL508a allows one to do with respect to field terminals for grounding field devices. One might think that is pretty basic, but the way UL508a is written makes it not as obvious as one might think. In fact, there are a fair number of pretty common practices out that in the control panel world that routinely violate all three of these standards.

You also have to be able to deal with operators, safety, and communications with supervisory systems and other equipment. There are all kinds of ways to deal with these. There is no book that can teach you these things because they are almost always things that the end user decides on.

My suggestion is get a decent education and then get hired as a junior designer and latch on to someone who can help you along the way and can check your work for you, at least informally. After you get 5 or 10 years of experience, you will probably be pretty competent.
 
C

Curt Wuollet

I have to second Bob again. We get so many inquiries I don't even dare answer because someone seems to be in way, way over their head. Despite what the sales types say, in order to control processes, automate machinery and in general do automation engineering with much hope of success and safety, you really have to know what you're doing, not simply be able to run the software. Some of the tasks _are_ easy, and ladder logic is fairly friendly and the tools are attractive. But there wouldn't be so many multimillion dollar engineering firms if just anybody can do it. And you're not an automation type simply because your company says you are. Very few jobs require such a broad array of knowledge and talent. One of the most popular questions seems to be: "How do I become qualified without all that education". Simple answer, you don't. Either from the ivy covered halls or the school of hard knocks or best, from some combination, you have to pay your dues. And never stop learning.

Regards
cww
 
D

David Ferguson

Even though we have heated arguments over which equipment to use to accomplish this, I agree 1000% with Curt on this and couldn't have said it better....

Dave Ferguson
Control Systems Engineer
 
C

Control_lurker

And don't forget to completely read the entire "fine" manual of the components that are purchased. Manufacturers put that information in the manual for a reason. Most of the time they help you with the design, if you just ask them. If you don't understand what the manual is telling you it means you need to ask more questions. Find out why the manufacturer wants you to know the information. It could be for safety, ease of installation, compatibility with other equipment or some other reason. Lastly don't forget to read all the manual "notes" thoroughly. These are usually glossed over by designers/ installers to their peril. Notes usually tell the installer why the particular product will fail to work in the selected application. Failure might have been avoided if the notes had been carefully read and understood.
 
B

Bob Peterson

Did someone say it was pointless to read books about designing control panels or HMIs? I don't recall anyone saying that.

No matter what the book promises, or what you might hope, you cannot learn to design panels solely from reading a book.

--
Bob
http://ilbob.blogspot.com/
 
Top