Advice

Hello Everyone,

I've gone thru all the threads for the past 2-3 months that would deal with my question. I do have a degree and studied controls and electronics. The controls I dealt with were dsp based type of stuff (state space/vector, optimization, observers, etc). All the electronics were advanced analog, cmos chip design and optimization, multi order active filters and RF (not microwave)stuff . I spent alot of time prior to school doing alot of embedded microcontroller stuff and eventually was a TA and did alot of robotics research (using microcontrollers). I am familiar with dsp implementation, digital/logic theory and kmaps (one project was to design an 8 bit ALU using pass transistor logic). Anyways I had worked in an integrated systems division at a company to get exposed to industrial instrumentation (don't reinvent it here)field. There I just basically pieced together customer systems from our product lines and with other manufacturers sensor products, etc. We had alot of custom hardware we sold so alot of things that we just needed to configure, not much plc experience. I'm familiar with 4-20 mA, what modbus is, putting together LOS radio links (and specing them), modems, cell modems, etc. I however never got any experience with a PLC in our out of school. I signed up for a community course and got the low down and simple programming ladder logic on a slc-500. I want to build upon my knowledge. The company I am working at (past 3 yrs) had an instrumentation dept when I was hired but the main guy (with 15 yrs experience) had a break down and never made it back. I've been stuck doing alot of 3 phase power(lucky I took alot of electives) design now. They've hired an experienced person who told me he just piece mealed it (he's mech engineer) over the years. I was thinking of getting some automation direct plcs so I can mod bus them and get better ladder logic and plc pid stuff. I am aware of your directs to learning pit and the intermediate plc programming and lab manuals that are offered here (but haven't ordered them yet). I also read about the Program Logic Controllers: Emphasis on design & application. I am still a year away from qualifying for my PE however I want to move into instrumentation again but my lack of plc experience limits me. Should I purchase those materials and a decent low end micro plc (that has PID) ability and just mock up a demo using fans, lights, etc? I know this is long but I know you can help.

P.S. I already own this book but haven't gotten to far nor have purchased a plc yet. http://www.amazon.com/Programmable-...=sr_1_7?ie=UTF8&s=books&qid=1253838180&sr=8-7

My PLC teacher recommended this slc-500 book http://www.amazon.com/Programmable-...=sr_1_1?ie=UTF8&s=books&qid=1253838419&sr=1-1. They (slc's) seem pricey for me just to obtain one to learn on. Anyone have experience with this book to justify the purchase (used of course)? The local AB rep has been here before to talk about their drives to my elec dept but refuses to lend out a slc for any period of time.

Well the best way to learn is to get the hardware and use the software. I'm 100% self-taught so I know it can be done. If you are motivated and want to figure it out you can do it. Also - It really helps to be around working PLC applications to be able to analyze the code to figure out how other people have done things. For example if you really understand how a machine works and then you analyze the program, you get more out of it then if you just look at sample programs. Hope this helps...

I would look at a MicroLogix 1100

You would be using RSLogix 500 software, same software as the SLC's (you would have good support here for questions) and you can get the software for free http://www.plctalk.net/qanda/showthread.php?t=46036

They also have analog built in, so when you got past the digital you could move to analog and do some ethernet...

welcome to the forum ... that's an excellent write-up – but here are some additional questions for you ...

(1) what's your budget? (less than $2,000? ... up to $10,000 ... other?)
(2) what's your deadline? (weeks, months, years?) ...
(3) what brand (and platform) is "selling" and/or "being used" in your sphere of influence? ...

even though it might seem like the cheapest way to get in the game, I personally never recommend "just-learning-the-basics" using "any old type of PLC that comes along" ... there are SO MANY differences in the programming software and in the way these things operate, that it's MUCH better to concentrate (as much as possible) on the brand and platform that you're planning to work with in the long run ... if Automation Direct is popular enough in your area, then by all means go with that brand – those are nice little systems at very attractive prices ... on the other hand, many (most?) people in your shoes would take a serious look (for better or for worse) at Allen-Bradley – and probably go with the ControlLogix platform – given the objectives that you've posted so far ...

so how much time (weeks, months, years) do you plan to invest in this "learning PLCs" project? ... note that you CAN learn it yourself on your own – if you've got the time and the motivation to do it ... and – the good news is that the forum members will be delighted to help you along FOR FREE ...

if you're like most people just starting out, the biggest advantage to taking some type of training "up front" is to compress the learning curve (time wise) into something that makes sense for your particular timeframe ... just do your homework before you invest the time and the money into taking a class ... suggestion: ask the forum for advice from people who have actually taken a specific training course before you sign up ...

DISCLAIMER: personally I teach "PLC programming" classes from time to time ... rather than give you a "sales pitch" I'm going to recommend that before you do much of anything else, take a look at the following thread on a sister PLC forum ...

http://forums.mrplc.com/index.php?s=&showtopic=6400&view=findpost&p=25957

pay special attention to the "self help" plan that I recommended in post #7 ... notice that I recommended that the original poster put in the time and effort to "learn it on his own" – with help from the forum members ... that pretty well sums up the advice that I'd give to you – as long as the timeframe fits into your career objectives ...

I wish you the best of success with your future endeavors ... please keep us posted on how things work out for you ...

Any given PLC is just a tool. Treat it as such. Don't get too hung up on the tool. Reading your circular saw manual really doesn't tell you how to cut a 2 x 6, much less tell you how to build a house.

If half of what you stated in your post is correct your lack of plc experience isn't going to hurt you too much. There are a couple of concepts that will be a bit foreign to you (like the plc OS will automatically cycle through the program) but by and large general programming concepts tend to apply. Since there are VERY few pure programmers in the field your big challenge is going to be system analysis, concept definition and development and hardware familiarity. All of these items are largely plc independent.

Keith

Welcome to the caos known as 'industrial automation'! For a beginner that really wants to learn, I would outright and extensively suggest a direct logics PLC from automationdirect. They are fairly inexpensive, offer a variety of equipment that would suit what you would like to do, including 'PID' controlling. They are also, in my oppinion, one of the easiest to program and understand, the software is cheap (under $200), you wont need 2000 cables and modules in order to connect your PC, like Allen-Bradley, and not to mention, you wont have to hold a $2500.00 service contract in order to call with questions. Their techs are very knowledgable, and eager to help. The only downfall is they are not accesible 24-7, and the quality of the products aren't up to Allen-Bradley. But they are better than some, and for your applications(for learning), they are more than adiquite. Regards!

Well everyone has budget. I was thinking no more then a thousand total. I was planning on taking an intermediate plc class at the local community (with the slc-500) but it was just canceled because they didn't have enough people enrolled (2). This is why I posted the advice thread. I realize from other posts that programming full time is out of the question.

As for a specific manufacturer,well we never spec one, we leave it as one of the follow types from spec master. I know from punch lists and all I have seen square d, siemens, ab and omrcon (I believe?). I see plenty of ladder logic from as built submissions however I never see a detail from the mechanical process people to compare that ladder logic to what is subposed to happen. Our instrumentation person would review it and make sure all the paper work was submitted and it went thru a 1 week trial with demonstration that all systems are working (induced errors, faults, high high water, etc). I was thinking that a good project to test my skills was to try and automate my homebrew equipment. I can see this as a continual upgrade project. A friend of mine has a packaged unit that uses a mitsu. plc controller for a small chemical dipper/cleaner unit. He wanted it to be smarter to recoginze that instead of raise lower wait 10, turn on ultra sonic cleaner, lower, that once the basket was in the 2nd bin it would go back to the first and get the next basket. He needs the unit operational so it would be done entirely on emulation before it was implemented. As of now those are my only two opportunities to try and build some experience with plcs.

The test jig I was thinking of using were obviously alot of toggles, push buttons, indicator lamps, output lamps, output relays to sim motor starters connected to single phase fans. I did see that auto direct does have some 100 dollar vfds and was thinking of using those as well.

So as far as I understand things it appears I should
-stick with the book that was suggested (programming with the slc-500)
-stick with the existing micrologix book I already have
-purchase possibily a micrologix system

Anything else?

My time frame would be about 6 months but I wouldn't claim myself to be an expert. I have another question, when do you merge to the other programming standards (besides ladder logic) for your project. I imagine function block being all custom blocks that are programmed together, etc but am not sure.

Hi jstantherprsn (Just Another Person, nice!),

If you plan to work internationally, which your grammer tends to lead me to believe you might. You should check out what systems are popular in your target countries.

A travelling Engineer with diverse knowledge can make big bucks!

Here is a link to Hugh Jacks PLC book: http://sites.google.com/site/automatedmanufacturingsystems/

Version 6 is online HTML, you can also download previous versions in PDF. Its a good place to start.

"So as far as I understand things it appears I should
-stick with the book that was suggested (programming with the slc-500)
-stick with the existing micrologix book I already have
-purchase possibily a micrologix system "

Again, If you are only planning on 'playing' at this point, this is the expensive way to go. If you do not already have the software, you are looking at about $8000.00 as a starting cost. Last time I checked, software (both RSLogix and RSLinx) run about $3000.00 combined, service contract, again, last I knew, was $2200.00 and $1500.00 per year to maintain, cost of cables and modules would run anywhere between $150.00 to $700.00, depending on the controller you choose. A micro 1000 runs between $800-$1200, depending on your needs, and PID controls is at the high end of that. So in all, once you put that all together with power supply, and controls, your cost may be more than you bargin for. Of course, I haven't delt w/ A-B in years, because of the simplicity and economics of automationdirect, so due to the economy and other factors (compatition) they may be a bit cheaper now, I don't know. But if MONEY is NO factor, by all means, ALLEN-BRADLEY.

ps, the last SLC-500 I purchased, cost me $12,900.00, 6 years ago. This included the rack, cpu, 3 digital input cards, 2 digital output cards, 2 PID temp control analog cards and a analog input car. I would definately do cost research and analasys befor purchasing anything.

NACarnes said:

"So as far as I understand things it appears I should
-stick with the book that was suggested (programming with the slc-500)
-stick with the existing micrologix book I already have
-purchase possibily a micrologix system "

Again, If you are only planning on 'playing' at this point, this is the expensive way to go. If you do not already have the software, you are looking at about $8000.00 as a starting cost. Last time I checked, software (both RSLogix and RSLinx) run about $3000.00 combined, service contract, again, last I knew, was $2200.00 and $1500.00 per year to maintain, cost of cables and modules would run anywhere between $150.00 to $700.00, depending on the controller you choose. A micro 1000 runs between $800-$1200, depending on your needs, and PID controls is at the high end of that. So in all, once you put that all together with power supply, and controls, your cost may be more than you bargin for. Of course, I haven't delt w/ A-B in years, because of the simplicity and economics of automationdirect, so due to the economy and other factors (compatition) they may be a bit cheaper now, I don't know. But if MONEY is NO factor, by all means, ALLEN-BRADLEY.

Click to expand...

FYI,
If the OP gets a ML1000 or ML1100 the software is FREE. See post below.

http://www.plctalk.net/qanda/showpost.php?p=340644&postcount=3

do NOT rush out and buy this, but just for discussion I've attached a screen shot of the type of stuff you can find on eBay ...

the "good stuff" RSLogix500 software would run you about $1,200 ... ten dollars should get you a null-modem cable ...

please clarify something for me ...

from your initial post, I got the impression that you were looking into this as an "income producing" career enhancement ...

your later posts seem to indicate that you're interested in "learning for personal improvement" - or something along those lines ...

your actual goals and objectives should have a LOT to do with how you go about this ...

Carnes,

Do you know if I could get a card for a quad encoder using the automation direct plcs? I will contact my ab rep and ask him about the micrologix and programming. It does appear you can program offline and upload the software without paying for a license. Thanks for the info about the slc-500 costs. That's pretty steep, I'm not rich.

Ron,

I am see this as a career move and keeps my doors open. My company wants to rebuild its instrumentation dept. If I can't move into that dept within the next year or so. I'll contemplate moving back into electronics. Originally I was hired to do power and instrumentation and due to the bre As for doing things personally, I was just trying to come up with machines. I don't have access to machines to test my plc skills on (like what was suggested). My friend has a machine for work that he wants to update to become more of a process machine. He's located 150 miles away and I don't see him that often to justify the commute. I could see the programming taking a few months. So I thought why don't I create a small process (homebrew) using my own personal homebrew stuff that I already own as an application to build my plc skills on.

You're welcome, and Yes, either a CTRIO card, or a CTRINT card, depending on the application. They do make them for all of their line except the 305's (I believe), including one of their micro PLCs

Ron also has a very good point, you can find some pretty good stuff on e-bay and other such sites, but be careful, always look for at least a 30 day guarentee, so you don't get junk! Also, in agreement with Mickey, they do offer 'kits' and software specials, but you are still looking at substancial costs if you plan to stick with the SLC-500 family. And the 'free' software may be a 'lite' or limited version. Something worth looking into though! Regards!