PLCs\ladder logic in the high school?

I teach in a public high school with grades 9 and 10 students (average age 15/16 years). We are not a trade school. The classes offered in our Technology Education department are electives for the students. We have a two semester course offerings titled “Robotics I & II”. These classes have evolved from a “Power Tech” and “Automation” background. We view robotics as an aspect of automation. We are currently involved in a curriculum rewrite and are in need of some advice.

A few weeks of the course has the students programming PLCs with ladder logic through a teach pendant. The PLCs control sensors and pneumatic cylinders to perform functions in a simulated assembly scenario. The PLCs used are GE Fanuc series one juniors and a GE Fanuc 90-30.

An “expert” in the field of robotics education has recommended we drop the PLCs and ladder logic in lieu of an assembly type project using the VEX robotics system and roboC programming http://www.robotc.net/vex_full/ . VEX was developed by CMU and is a highly configurable erector set type kit with a programmable “brain” and numerous input/output options. We currently have a number of the VEX kits used in other parts of the curriculum. My fear is that we should not remove the PLCs and ladder logic components because of what a fundamental niche of automation they fill. Please remember that we are not a trade school and our courses are designed to fulfill the needs of students who will pursue a wide variety of higher education and career options.

Remove the PLCs? Remove the ladder logic? Update PLCs? If we should update the PLCs can you recommend a replacement PLC? If we should update the PLCs can you recommend inexpensive but intuitive software that utilizes ladder logic?

Thank you in advance for sharing you expertise. Scott Downs

The Ge Fanuc is still used a lot in the industry. Omron PLC's tend to be less expensive than Allen Bradley however its software is not as easily understood as Allen Bradley. Others may have differing opinions however after studying some of the different manufacturers I find that teaching for Allen bradley a lot easier than in other platforms. For this I usually use a micrologics controller However unfortunately The software and hardware isn't cheap

Scott,

As you had mentioned...you are not a trade school but offering an introduction into automation.

Ladder logic has been around for many years and will still be around for many years to come.

As for an alternative, we offer a free programming package and a discount for schools off of our hardware.

Every student can have their own software and it won't cost them or the school a dime.

Here is some additional information from our web site.

www.entertron.com/plc_training.htm

If you are interested, feel free submit our product recommendation form and I will send you the password for the software for evaluation.

Hope this helps.

God Bless,

Note - I am employed by Entertron.

There are far more PLCs than robots in use in the manufacturing world, so your students are much more likely to be working with PLCs. In addition, we've been hearing blather about the imminent demise of ladder logic as a programming language for a couple of decades now but it's still in widespread use.

The Series One Junior has been obsolete for more than 15 years, so that should be the first platform to retire. Even though the 90-30 is getting a bit long in the tooth, it is still a viable platform. In fact, if you can get your local GE Fanuc people interested in helping you upgrade to the RX3i platform, your I/O modules will still work with an RX3i CPU and any "standard" programs you may have produced for the 90-30 can be imported into a new application folder for the RX3i.

If I were you, I would talk to your local GE Fanuc distributor. They probably helped set your school up with the hardware you have and may still be willing to work with you. Furtehrmore, they will know what industries in your area are using their hardware and might be able to help you arrange field trips to show your students some real-world applications.

Fanuc is also a player in the robot market, but the GE Fanuc joint venture only involves PLCs and CNCs. It does not extend to robotics. The GE Fanuc rep may be able to put you in touch with the Fanuc robots rep.

PLCs are everywhere and growing - they are even making their way into the home.

Your expert is either
A) a salesman.
B) an academic who has not been inside a modern factory recently.

Greetings sdowns ...

and welcome to the forum ...

A few weeks of the course has the students programming PLCs with ladder logic through a teach pendant.

Click to expand...

let me ask a question: what do the STUDENTS want to do? ...



specifically, do they act more “interested” in the PLC part - or more “interested” in the robot part of the course?



specific reason for asking: with only a few weeks of time (and probably not five full days a week at that) then the amount of PLC Ladder Logic that you’re going to be able to cover is probably “less than a lot” ... and (no offense) the teach pendant approach is not likely to be directly applicable in the field ...



so ... if you can keep the students “engaged” and “interested” in learning ANYTHING about the subject of automation, then I’d suggest that you plot your course accordingly ... if that happens to be more “robots” than “PLCs” then so be it ...



BUT ... ON THE OTHER HAND ...



I got started in the automation field by taking a two-year “robotics” course ... one or two classes were devoted to PLCs - but more or less as a “well-while-we’re-here” type of afterthought ... now here I am about twenty years later ... I haven’t touched a “robot” since leaving school ... but I’m able to make a very decent living just teaching PLC skills to plant maintenance technicians ... while I’m sure that some of my distinguished colleagues would debate the numbers, I’d personally guess that for every ONE job in America today that focuses on “robots” there are probably at least ONE-THOUSAND jobs that deal with PLCs ... most of these jobs aren’t “programming” jobs - but there’s still a LOT of work out there that requires PLC skills ...



so ...



your decision might hinge upon this:



(1) you might choose to keep your young students “engaged” in learning by teaching them something “interesting” like robotics - even though they’ll eventually have to switch gears somewhere along the line to make a living ... or ...



(2) you might choose to teach your young students something more likely to be potentially “useful” like PLCs - even though they might tend to drift through the class with little or no interest or retention ...



the major idea is that you’re dealing with YOUNG students who are highly unlikely to go straight from high-school into the workforce ... with that in mind, I’d consider it important to expose them to a wide variety of subjects - and hopefully get them interested in the automation field ... specifically, I wouldn’t tend to worry too much about how useful each specific topic might be in the long run ...



a final thought: you should consider making interesting “mainstream” assignments that will keep most of the students “engaged” and “learning” ... and also have “extra credit” projects available to challenge the one or two students (bless their hearts) that are motivated to get as much out of the training as possible ...



hope this helps ... I wish you the best with your project ...

Building on what my distinguished collegue Ron has said, you could also consider using a simpler pick and place robot controlled by a PLC - which is by far the most common kind of robot and the one most likely to be enountered in the work place - thereby blending the two together.

Not a lot to add but you are asking a PLC forum should you keep the PLC's???

I, like others say YES keep the PLC's, there are many PLC's that offer free software or discounted to the point that it will fit into your budget...

You can also read this thread http://www.plctalk.net/qanda/showthread.php?t=37671 as you may want to include an HMI to get more of an interest of the students

Just a thought...

just in case my main point was missed, I personally think that PLCs should definitely be included in ANY automation course ... they're a part of automation that no one involved in the field should be ignorant of ...

As Ron said in his first post, you may need to cater to their expectations a little bit. By calling your program 'Robotics' you will have students walking through the door thinking they will be building a cheap version of Honda's Asimo. Once you beat down that expectation you will end up with this as the next thing in their mind. If you crack out a plc and a couple of pneumatic cylinders you are going to lose them in a hurry. These students are your customers. Managing their expectation will be the most difficult part of this endeavor.

Having said that I also agree that focusing on automation designs using plcs is much more practical. But are you really looking for 'practical' in the usual sense? If your main goal is to show that automation can be a 'fun' career choise and you aren't looking to jumpstart them trough a couple of tech school classes keep it fun even if it isn't practical.

Keith

Like most have already said. PLC's and ladder logic are definatly not going away anytime soon. Here is how I look at it simply.

With a few exeptions if it is a standard setup without much precision movement you should bet on that its controlled by a PLC. That means that in order for the adverage maint tech you will need to use something there used to looking at it. I.E. Ladder diagram type stuff. That is Ladder logic.

This of course is comming from a Automation Tech that has to program things for maint techs so I dont get called at 3:00 am.

I know what I would chose if I were a high school student

I like the Vex robot kit. Perhaps I am bias towards things that move.

I don't see why you would get rid of the PLC course--lots of budding automation engineers attend high school. Being exposed to PLCs in High School might help people make a career choice...

Take a look at the Horner Electric website. You can download their software for free. The look and feel is very similar to what you would find with the GE PLC ladder. The hardware is reasonably priced as well. I would expect that Horner could arrange special pricing (or perhaps even give free samples) for educational purposes...

http://www.heapg.com/

PLCs / Ladder Logic in High School

If you're worried that your students will be disappointed not to be working on R2D2, remind them that robots are already here. A washing machine is a robot, a telephone answering machine is a robot, and a redi-mix concrete plant is just a very big robot. Robots don't need to be androids - and few of them will be.

I think I'd start a class like yours with relays. We all know the history. Diagramming relay logic led to the ladder logic drawing style that dominates PLC programming. And no one escapes relays - open any industrial control cabinet and there you see relays and motor starters. Programmable output boards end in a row of relays.

If the class needs show business appeal, build a wheeled robot with a PLC brain. A simple line tracker can even work with less than a dozen brain cells (relays).

A program that mimics RSlogix 500 and that I used when leaning is found at www.thelearningpit.com LogixPro is an inexpensive way of learning about PLC's. It has different scenerios that you can try and write code for and actually test it out to see what happens.


Only drawback is that there is no wiring ect, just strickly on the computer, but for the cost it is well worth checking out!

Mark