Gaining experience with Allen-Bradley PLCs when your company does not use AB.

I've noticed that a lot of recruiters are looking for Engineers with experience in Allen-Bradley PLCs to fill positions, and I have two questions regarding this:

1) How do AB PLCs differ from the 'standard' of PLC programming; design in Ladder Logic, build in emulator/communication software, upload to PLC?

2) How could someone gain experience with AB PLCs when their company does not do much in-house automation design, and only uses Omron PLCs on the rare occasion that a PLC is added to a project?

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Hi Andrew.

First question, i suppose, would be to ask, what is your "standard" PLC? A number of markets refer to A-B as the standard and it usually is in North America.

The broad answer to this question would have to be the memory organization. Whereas most PLCs, such as Omron, have a linear memory map and predefined areas, A-B organizes memory in a somewhat flexible file structure. Aside from the standard (predefined) data type files (B3 for bits, T4 for timers, C5 for counters, etc.), additional memory space is user defined. If you were to run out of timers for example, you might define a new timer file as T9 - giving you an additional 256 timers to play with. These files contain up to 256 of any defined type, which presents a problem when trying to store any significant data.

Minor differences in programming include one-shots, the toggling of bits, and the handling of timers, but these things are all pretty easily assimilated by your average geek.

As to gaining experience, you might try to find a training program at your local community college. Due to the expense, most colleges focus on one manufacturer's line of hardware, so you would have to scout around for one using A-B. A few colleges with a larger investment will teach on multiple platforms.

Another possibility might be to try the software simulator route. I'm pretty certain that A-B has one, although i don't have any idea of the price. If you're the self-starting type, you could take on a small A-B project on the side. This may be complicated by conflict of interest rules, but is a sure way to figure something out. Nothing like jumping in the deep end to learn how to swim.

Personally, i cut my teeth on Omron and found the memory organization of A-B to be the most awkward to get my head around. I've since written on most of the other manufacturers' hardware and i can tell you that it gets easier and easier with each new system you take on. Good luck.

Jeff
Thanks for the info, at school I was trained on ladder logic as the primary way of writing PLC programs, and the programs we were writing in class spelled out which inputs, outputs and internal functions were available. In the labs we were programming AutomationDirect PLCs if memory serves, but again, we were writing 'textbook' code, not using any special features in the PLC or 'tricks' such as overwriting register values. We were being taught to treat the PLC as a firmware-based simulation of a Relay Wall, so the programs we were writing could be compiled in ANY model PLC or even wired up by hand out of discrete relays and it would work.

Here at the plant, the normal choice for PLCs in a project is the Omron Zen series, which can be programmed from the controls built into the PLC housing, and the 'right' to program and maintain the PLC's is being jealously guarded by the maintenance Department, which was doing the programming before the company decided to hire an Engineer.

I think I'll get in touch with one of our suppliers who handle AB systems and see if they have any 'student' or 'trainer' software packages to help the people here get used to the AB programming layout prior to bring in the AB PLCs to the plant.
A possible source of training might also be your local vendor. Mention that you would like to do a comparison between the Allen Bradley product line and the Omron PLC. Most of the time, they will offer to give you a demonstration and may actually offer to leave you a demo unit for a few days. We recently made the switch to Allen Bradley, and I was amazed by how much the vendors were willing to do while we were in the decision stages. It certainly can't hurt to ask.
ARE OMRON PLC ARE GOING OUT OF BUSINESS, AND MICROTECH 11 TAKING OVER
Invite competitive PLC bidders on site. Be fair. Be all inclusive. Be diverse.
Inform management, maintenance, operations, enginering & PLC vendor that PLC functionality, plant cost effectiveness, and improvement analysis is being performed by the Engineering Dept.
Evaluate benefits and ROI. Total cost and benefit shall not be limited to initial PLC cost but rather, operational improvement, plant energy savings, reliability, redundancy, risk assessment, automatic performance, plant operational savings in reduced effluents, reduced greenhouse gas, reduced energy, offset carbon credits, increased tax benefits from energy conservation and the potential for federal grants, loans, and tax benefits.
Mention potential to improve product, optimize cost, increase jobs and raise job qualifications. Provide potential for on-site programming training and specific programming benefits to quality and cost of end product and inhouse personnel.
Basically, be an engineer, not a maintenance pansy.
Hi Andrew,

Kudos to you that you are actively working to broaden your scope of knowledge beyond what you typically do in your job - many people do not show that much forethought in career planning. When trying to broaden your AB knowledge, be aware that there are a couple of programming styles with AB -- tag-based programming that is commonly associated with the Contrologix PLC line, and the addressed based style, associated with Micrologix, SLC500, etc. The address based style will be most similar to what you are doing in Omron.

You should also take a little time to learn the IEC61131 style of programming that is used many other PLC manufacturers such as Bosch Rexroth, Wago, Phoenix, Moeller, B&R. Because it's a (mostly) standardized language, learning one manufacturer's programming style gives you expertise in dozens of others.

I would agree that starting with a distributor for a particular product is a good way to start, but beware that any presentation will be at least somewhat biased towards the product of choice, so keep an open mind. In the current economy everyone will be fairly eager to impress you, especially if you have an actual project to do.

Regards,

Ted
Linda Jayne said:
Invite competitive PLC bidders on site. Be fair. Be all inclusive. Be diverse.
Inform management, maintenance, operations, enginering & PLC vendor that PLC functionality, plant cost effectiveness, and improvement analysis is being performed by the Engineering Dept. Evaluate benefits and ROI. Total cost and benefit shall not be limited to initial PLC cost but rather, operational improvement, plant energy savings, reliability, redundancy, risk assessment, automatic performance, plant operational savings in reduced effluents, reduced greenhouse gas, reduced energy, offset carbon credits, increased tax benefits from energy conservation and the potential for federal grants, loans, and tax benefits. Mention potential to improve product, optimize cost, increase jobs and raise job qualifications. Provide potential for on-site programming training and specific programming benefits to quality and cost of end product and inhouse personnel.
Basically, be an engineer, not a maintenance pansy.
All good advice, however the level of inertia in the plant is staggering. Three years ago the company decided that they needed an Engineer on staff to run the 'experiments' that were being done at the time by the department heads. All of those projects have been canceled by the department heads as they proved to not be a quick solution that worked flawlessly. Everyone talks about automating, but nobody wants to release the money from their budgets to run any REAL testing to improve the production flow.

As far as 'being an Engineer, not a maintenance pansy,' It is difficult to step up to making plantwide recommendations when your position on the Organization Chart has you directly under the Molding Superintendent. Anything that does not increase his ability to produce more product is considered a 'waste of time.'

Even an automated inspection station that would decrease the time the QC department needs to do a full round of inspections is considered a waste, since that is for 'another department,' despite the pitch that it will provide the knowledge necessary to design and build a 'fire and forget' inspection station, where the parts are dumped in at one end, measured and sorted, and the good product, along with a report, comes out the other end.

And as far as ROI is concerned, the 'upstairs offices' consider anything over 24 months to be too long, and the Molding Superintendent treats that as Gospel. Any new 'tech' that costs money has to prove that it will pay for itself in two years or it is not purchased.

I'm afraid I'm taking my own post off-topic with this little rant. I'm supposed to be looking for advice on improving my PLC skills, not venting about the resistance to change in the plant.
Andrew, I don't have experience with AB, but from my experience in working with PLCs and PACs (from ICPDAS), there is more to life than ladder logic. Take for example Red Lion's Crimson software and G3 series HMI/Controllers. For one, its free software. Two, you can get remote I/O working in less than 2 minutes without even reading the manual (help files). Three, you can simulate with real access to serial and ethernet ports. Four, built in touch screen.

A recruiter that touts experience with AB as a must is just a "name-thrower". Either the recruiter has no idea what they are looking for in an Engineer or is using an outdated copy of a job description. What's more valuable to a company, someone who knows ONLY AB and nothing else, or someone who can work with any system (regardless of programming method) and get a solution working well. The strength of an Engineer is the ability to find a solution with what he/she has available and to seek opportunities to maximize profits, minimize workload, increase reliability, question everything, etc..etc..the list goes on.

Finally, don't let the lack of AB knowledge keep you from applying to these positions. When the time comes in the interview, I'm sure that having Omron PLC experience proves your ability to understand the basic concepts, now its just a matter of applying it in a different language.
Thanks for the support, I feel the same way about learning the 'core fundamentals' that apply across a whole category rather than learning 'a brand.'

The story that let to the original post was a conversation with a headhunter, where all the positions he was hiring for had Allen-Bradley mentioned by name. When I mentioned my 'generalist' PLC training, he basically pointed out that the companies he was hiring for wanted A-B experience specifically, and that was a 'deal breaker' term. In short, the instructions he was given was to disqualify anyone who did not have 'the mark of the beast,' to steal a biblical analogy.

I also understand that PLC and their close cousin, PAC, work in more than just Ladder logic. From my self-training on a programmer/emulator from TriLogic, I found that the additional features are implemented as 'code packets' or 'subroutines' that run when their 'control point' is triggered,

I'm also aware that PLC programs can be viewed and edited in different ways, such as the ladder logic chart or as assembly code. Different representations of digital logic are good for different things. Boolean Algebra works best when 'simplifying' a complex digital circuit that does not have any 'race conditions.' The logic symbols most often used for TTL (and successor) systems work best when looking at circuits that have complex interactions between many sections, and 'race conditions' need to be controlled, either to minimize their effects or to use them to shape signals, such as detecting a rising or falling edge. Ladder Logic is best for looking at a number of circuits that, in theory, will all run simultaneously and for the most part independently of each other, just like the 'relay wall/relay room' of yesteryear.

David Rojas said:
Andrew, I don't have experience with AB, but from my experience in working with PLCs and PACs (from ICPDAS), there is more to life than ladder logic. Take for example Red Lion's Crimson software and G3 series HMI/Controllers. For one, its free software. Two, you can get remote I/O working in less than 2 minutes without even reading the manual (help files). Three, you can simulate with real access to serial and ethernet ports. Four, built in touch screen.

A recruiter that touts experience with AB as a must is just a "name-thrower". Either the recruiter has no idea what they are looking for in an Engineer or is using an outdated copy of a job description. What's more valuable to a company, someone who knows ONLY AB and nothing else, or someone who can work with any system (regardless of programming method) and get a solution working well. The strength of an Engineer is the ability to find a solution with what he/she has available and to seek opportunities to maximize profits, minimize workload, increase reliability, question everything, etc..etc..the list goes on.

Finally, don't let the lack of AB knowledge keep you from applying to these positions. When the time comes in the interview, I'm sure that having Omron PLC experience proves your ability to understand the basic concepts, now its just a matter of applying it in a different language.
Hi Andrew:

I know exactly what you need. Review the details and sample of the 2 CD PLC Training Set, it is designed on AB's RSLogix 500. An excellent starting point. But it doesn't give you much experience uploading and downloading. For that you need the ABS01 Micrologix Trainer (Training equipment with actual PLC and lessons on CD.)

While we offer PLC training in every conceivable format, I believe the above to be the most cost effective solution for you.(The PLC Training video library is the most exstensive PLC training, but pricey. :>)
Hope this helps.
Don
Thank you for the sales information, however it is unlikely to convince the company to release money from the budget for training aids in PLCs that aren't used at the plant, and I am not going to try and purchase something like this out of my own pocket.

Donald Fitchett said:
Hi Andrew:

I know exactly what you need. Review the details and sample of the 2 CD PLC Training Set, it is designed on AB's RSLogix 500. An excellent starting point. But it doesn't give you much experience uploading and downloading. For that you need the ABS01 Micrologix Trainer (Training equipment with actual PLC and lessons on CD.)

While we offer PLC training in every conceivable format, I believe the above to be the most cost effective solution for you.(The PLC Training video library is the most exstensive PLC training, but pricey. :>)
Hope this helps.
Don
Sorry for the "sales" Andrew. :>) But most people looking to improve their own personal marketability in the job market, seem to find the $159 for the 2 CD PLC training set on their own. (If they discover the job market is demanding Allen Bradley knowledge like you mentioned in your original post.)

I was merely providing the best answer to your question. The generic reply would be...
If you feel you need to gain more knowledge of a certain PLC brand to improve your career, invest a little in yourself and purchase some specific training. :>)

I recommended the 2 CD set because it is relatively inexpensive and you get so much knowledge out of it. (A great value.) If you think the my intent is self serving, don't buy the CD set from my company, buy it from Koldwater. That way we won't make a dime off of my advice. There are other sources to purchase the training too, besides from us or Koldwater, but you will pay a lot more.

hope this clears up my intent. :>)

PS: The expensive training video set I mentioned is generic in nature, so maybe your company would purchase it, although you probably do not need that generic training. It sounds like you just need to learn AB specifics.


Andrew Dreasler said:
Thank you for the sales information, however it is unlikely to convince the company to release money from the budget for training aids in PLCs that aren't used at the plant, and I am not going to try and purchase something like this out of my own pocket.

Donald Fitchett said:
Hi Andrew:

I know exactly what you need. Review the details and sample of the 2 CD PLC Training Set, it is designed on AB's RSLogix 500. An excellent starting point. But it doesn't give you much experience uploading and downloading. For that you need the ABS01 Micrologix Trainer (Training equipment with actual PLC and lessons on CD.)

While we offer PLC training in every conceivable format, I believe the above to be the most cost effective solution for you.(The PLC Training video library is the most exstensive PLC training, but pricey. :>)
Hope this helps.
Don

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