Learning PLCs .... relatively quickly

Hello,



My name is Ettore (‘E’ for short) and I am a newbie EE straight out of University. I was recently hired by a small engineering/CAD firm who are in process of expanding into a full-fledged manufacturing/engineering facility in the next, say, year or so. Part of this expansion plan was to take their biggest money pit -paying outsourced controls guys for their controls stuff- and hire a new guy (me) to do it instead.



Well, this is a GREAT opportunity for me because I am now the only EE guy here and, thus, top of the food chain in that respect. However, it isn't good because my employers do not appear to have an exact plan of how to get from here (newbie EE guy) to there (Controls/Pneumatics guru) in the 6 months that they have allotted. This is where (I am hoping) this forum and it’s plethora of expertise comes in.



The types of jobs that we generally deal with are relatively simple in nature. Lots of proximities, cylinders, etc in relatively small scale ($1,000,000 project would be HUGE for us). Most of our machines are designed to replace one person to maybe a few simple jobs but typically involve at least one robot (usually Fanuc or ABB). For example, we are currently designing a system that loads crates of spark plugs which are then staged onto a rotating pallet by our new robot. A second robot (existing) then picks them up from the staged area and installs them into an engine. If it matters, I have no idea what type of PLCs we typically use; nor do any of the people that work here. I saw one CAD drawing with a GE VersaMax and I know that one of our customers (at least) is A-B only.



Where am I now? Well, when I got here they had nothing for me to do so I started reading CAD/manufacturing standards for all the companies that we deal with. After I read those 10 times, I began looking through all current projects they are working on to get a feel for what's going on and how things work. That was day 1 and quickly ran out of written material so I jumped on the internet to hunt down some PLC knowledge; among my travels I found this place. I read the 'Learn PLCs' section on this site as well as on another site that was, however, mainly directed towards SLC 500 (something like that) PLCs. I then found PSIM and downloaded it off the programmer's website. I did all the tutorials and exercises … then redid them again to see if I could optimize my code even more; so that's where I am now. I feel that my knowledge of the basics of logic design and operation are decent … though I do know I need a lot of practice. I don’t want to seem like I think I am the king of all that is electrical, but I am pretty good with programming in basically every language I have had to learn. I learn quickly and don’t typically forget what I have learned even if I have only seen it once. I want to be a go-getter in this job because it’s my first real-world employment and it’s intriguing and kind of cool (to me anyways) … especially for a first job.



My main question is: What should I do next? If I wait for my employers to come up with solutions I believe it will take MUCH longer to progress than I am capable of. The only tools I currently have are the laptop they bought me and my desk (it’s quite sturdy I might add). If I suggest ANYTHING, they will get it for me but I don’t want to be asking them for $10,000 worth of stuff that I don’t need (just yet anyways). Are there any books that are relatively cheap (say, under $200 CAD) that would be an asset to a budding EE controls guy? Are classes actually worth the thousands of dollars they charge?



Whatever I suggest to my employers, they will basically do. They are already asking me how much I am learning and they haven’t even done anything FOR me yet (other than, of course, pay me to read stuff). They say that I will be working with the current controls guys (the contracted ones) but I highly doubt they will be too anxious to help me when I have questions. They also want me to start programming their next machine when it comes up so I want to be ahead so it doesn’t take me 1 month to learn how to upload a freakin program.



So, any help would be GREATLY appreciated and everything you say will be considered. Hopefully Monday I will have a list of **** that I need and I can start getting myself organized. Thank You preemptively for everything … I need help J

First of all, welcome. You are diving into what can be simutaneously a rewarding and infuriating profession. But it's been my experience that it is more rewarding than infuriating.

As far as classes go, I would put that off for a little bit. This is a personal opinion, but I think you will get the most out of the classes offered by the manufacturers after you have some exposure to their product. You need to know what questions to ask before you can ask the questions.

The good news is you probably don't need to worry about the particular plc at this point anyway. The first thing you need to do, again IMHO, is figure out your process. You can't write software for something if you don't know what it's supposed to do. Put together as detailed a description as you can in any format you feel most comfortable with. Use flow charts, state diagrams, text descriptions or anything else that helps you conceptualize your machine and process. From that you can break down your machine into intelligent, manageable sections.

Once you have it broken down and you know how you want to proceed you can either start writing psuedo-code, again in any format you choose, or find out what your target platform is, get the appropriate programming software, and start going.

As you can see, sooner or later you need to know what your target plc is. But early on it doesn't really matter. Control and programming concepts and methods are pretty transportable between plc platforms.

It may not hurt to start asking what plc platform you will be using on your first project just so you can get moving with buying the software to program it. But don't worry too much if they can't tell you right now. I tink you have 'bigger picture' stuff to think about for a little while yet.

Have fun.
Keith

Pick out a simple project, get an inexpensive brick PLC like an A-B 1000 or an AutomationDirect DL-06, software, and cables. Then have at it. You will learn more that way than ever possible from just reading.

Get familiar with the kinds of automation hardware out there. When I'm breaking into a new field, I like to get lots of catalogs and just page through them. Start with broas line suppliers like Allen Bradley, Square D, Cutler Hammer, Phoenix Digital, Turk, Potter Brumfiled. It sounds like you are in motion contrl, so search them too. Get a subscription (usually no charge) to Control Engineering, ISA publications, Instrumentation and Automation News, and so on. For a begineer the adds are more help than the articles!

There are a number of threads on the site about getting started, with things like using a point list as the first step, and then ..... Read them and apply them.

At some point you may have to get some formal training from your most used PLC supplier. This is an investment for your employer.

Your situation sounds similar to mine several years ago. The company I came into (when I was still a student) already wrote their own control software, but the guy doing it was an AG-E. He's a brilliant guy and I've learned tons from him, and he still out shines me on Access database work, but the EE background helped out a lot more than the AG-E background when it came to writing control software. Basically when I first started I took over IT and started learning PLCs. For the most part if I ask for something I can get it; I just have to make sure I learn something from it.

I'll agree with Tom. Go get a cheap brick PLC and start working with it. It doesn't really matter what you write; just write something. My first program was a garage door opener using a DL205 system with a DL250 CPU. It was one very expensive garage door opener, but I learned a lot. My second program was a pool and spa control program, and I learned a lot more. Neither of these had anything to do with anything my company builds, but like you my bosses didn't care as long as I was learning.

Sadly I now have very little time for what I would call play projects, but when I get the chance I'm still known to use a PLC for something very simple just to do it.

I agree with Tom also. Get a small PLC and start playing. Its the best way to learn quickly. If you need a nudge in one direction or another from time to time you could likely get it here.

Another thing: To get an idea of how a project might/should go from conception to commission, read this thread from begining to end: http://www.plctalk.net/qanda/showthread.php?t=11015 it will show you how a motivated individual, with the proper attention to details can do anything with little previous expierance.

ettore said:

Whatever I suggest to my employers, they will basically do. They are already asking me how much I am learning and they haven’t even done anything FOR me yet (other than, of course, pay me to read stuff). They say that I will be working with the current controls guys (the contracted ones) but I highly doubt they will be too anxious to help me when I have questions. They also want me to start programming their next machine when it comes up so I want to be ahead so it doesn’t take me 1 month to learn how to upload a freakin program.

Click to expand...

I totally agree with the poster above that said that you first need to learn the process. Do you have access to any of the existing machines?
If so, take notes on how it works. Try to compile a sequence of operations. This type of sequence will be your guide when you go to program a new machine.

I also agree with the suggestions that you get a (relativly inexpensive) brick type PLC and get to work learning on it by writing test programs.

If there are areas of the programming/machine design that you do not understand (for example, flame safety design), do not be afraid to ask for help, or push to have those parts subcontracted out (at least until you feel comfortable taking on those responsibilities).

All good advice above.

I would suggest that you try to get downloads off of previous and present machines and start picking them apart - hopefully they weren't written by a 'bad' programmer - don't want to have to unlearn.

Also, you might look at any HMIs being used. Glue one on your new brick and wire up an encoder for grins.

You might start making boiler plate templates for documentation.

All I can think of.

Rod (The CNC dude)

His topic is the test that the entities of education -does not import the country- do not prepare for reality. Unfortunately, not capacity for will have immediate autonomy, leave stunned. Frequently the corporations require most minimum experience (time of apprentice), but in the reality signifies sense of orientation acquired.
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The best one that yourself can do here, is going to ask: "Which your strategy for" and to pray for have replys

Wow, thanks for the info everyone.

I don't appear to have access to any existing logic at this time but I do have access too all the electrical and mechanical drawings. I really want the damned logic.

Anyhow, I will be talking to my boss about getting me a PLC. This shouldn't be a big problem as I am sure someone we know has a few PLCs from decomissioned machines or just out of date stuff that was outright replaced just for update purposes.

Thanks for the information again, your opinions seem to basically reaffirm the path that I am currently on. I spoke with a controls guy from the company that we currently farm out our control work to and he said he is going to make me up a CD with some 'software' which I am hoping will aide me in viewing existing logic. As well, he seems to be showing up a LITTLE more often now that he knows competition is on it's way (me) and our large project we are working on is coming to fruition (sp?) in the very near future (we hope).

-- E

Oh, elevmike ... reading that post from beginning to end will take me all day.

Noting that, I will still probably do it because I have nothing else to do.

Now I have a bit more time for a complete reply:



I read the “Wire Cutter” topic (yes, all 55 pages of it) and was rather enlightening, to say the least. To see her progression over 4 months was inspiring, since you could see the definite progression almost page to page; excluding the surprisingly rare off-topic posts. I hope I can be like her, with respect to the way she attacked things and how she did her own research along with expert help when she was stuck.

If there are areas of the programming/machine design that you do not understand (for example, flame safety design), do not be afraid to ask for help, or push to have those parts subcontracted out (at least until you feel comfortable taking on those responsibilities).

Click to expand...

Being safe is exactly why I went through the University engineering system instead of the college system; it’s an interestingly different style those two, in my city anyways. University was supposed to be more safety oriented (Professional Engineer type stuff) so I opted that way (probably a mistake given the poor education I got); I digress. I won’t be the ‘main guy’ for a long time, they are farming in advisors and ‘inspectors’, if you will, to look over my code that I eventually develop. As well, my first machine (that basically doesn’t even exist in concept yet) will be completely programmed by me but will be 100% reviewed and troubleshot by me and the same aforementioned controls gurus.



Regarding the PLC, I am hoping to get some spare AB stuff but I am not holding my breath. I really doubt my boss would go for the AD stuff simply because it isn’t what they deal with but the AB might be doable; that would probably be my preference then I will at least have the software to program all of our Ford stuff.

Will update this post in a week or so and see where I am at with the new CD.

Are you doing only programming or also the electrical design. If you are, get your (I am not sure about Canada) codebooks. Also get NFPA 79. standard for electrical machinery.

You brought back some memories. I started exactly as you are doing 11 years ago. I was right out of school for a small 2 year old startup. I look back with some pride and quite a bit of cringing. It is hard without any guidance, but being the only controls guy has its advantages.

I tried to look into any control cabinet I could find, look at any schematic I could find, and read any program I could find.

If I had decent internet resources like here and others, it would have been a godsend.

There is a download section on this site and on others. Get those programs and dissect them.

This is actually an interesting question. Last night, just before I left, my boss asked if the panel/electrical drawings that he gave me for our current large project made sense to me. I said "Yes" not quite understanding what he meant by 'understand'.

Apparently, his 'understand' == can build it from scratch. So, now I am building a control panel and he's hiring me a panel guy. I had to reiterate to my boss that I "DO" understand it but not enough that I feel comfortable building one from scratch with no guadance by myself; he didn't seem to get it. So, now I am building a panel and relatively soon too because phase 1 is inside this panel along with the next 2 phases.

Anyone know of a good internet resource that can explain control drawings? I understand how everything connects, I just don't know what a normal panel LOOKS like in close detail (all the wiring is always covered). I really just need nice detailed exisiting panel images if possible, or some kind of blueprint reading tutorial or similar.

Take a look at this thread:
http://www.plctalk.net/qanda/showthread.php?t=8991&highlight=panel+pictures

For control drawings you can look at:

http://www.patchn.com

or look in the back of NFPA 79, if that applies in Canada.



What are you going to use to draw with? Alot of people seem to like AutoCAD Electrical. I use AutoCAd LT with these symbols:

http://forum.mrplc.com/index.php?&act=Downloads&CODE=02&id=146