PLCs\ladder logic in the high school?

[geniusintraining]

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

I like LogixPro and think its great BUT.... its great for people that know what they want to do
((make a living in the automation world and want to pull their hair out and kick them selves the rest of their lives for not becoming a doctor...))

Now for the BUT, kids now days can do more on computers then we have ever thought... they need more then just a screen turning colors

So there needs to be something else... a robot or something with motion.... the WOW! factor needs to be there

 

[sdowns]

Thanks for all the great replies and time. The last week or so has been a learning experience. I must add that I am actually not the person teaching the class (yet), but have been given the ball to work on the curriculum and develop activities to support. I haven't touched a PLC since college days.
The PLCs in our program have fallen by the wayside for the last few years and I needed to decide what to do with them. Did not take long yesterday after reading responses to decide that they will be upgraded. Now the fun part of developing dog and pony show activities. Trust me I know that it has to be fun to keep 'em interested. I will continue to monitor this post diligently for the next few weeks so please do not hesitate to continue the recomendations for hardware, software, and activities. Thanks again, Scott

 

[mordred]

One idea is to have a 3 stepper motor application with a photoeye mounted. have em set up the hardware and software to reliably get the laser to point to several predetermined locations.

 

[danw]

The qustion is whether a trade-off - specialized robotics programming for specialized robotics hardware fits the goal of the schooling, as opposed to ladder logic skills.

The answer to this question lies in the ultimate goal of your school. You've ststed that you are not a trade school, which has an implication that I'm not sure I understand, so I have to ask, what is the ultimate goal of your schooling?

Exposure to technology, with some fun hands-on for the worker in the pair (the other one always being the drone . . )?

Development of specific trade skills (which seems to me to be more a trade school objective), To provide students . . . . ?

A fun atmosphere of creative exploration of technological building blocks, a Montessori approach to technology beyond the Erector Set ?

I don't know, and I'm not making fun, but there are numerous alternatives in schooling.

To me, ladder logic, belongs in a trade school. But you're not a trade school.

If you goal is to have your students do better robotics, then using robotics hardware and software specifc for robotics is a better way to go. Then the question becomes is this specific brand the best approach for teaching robotics?

So, does learning robotics with specialized hardware/software fit the school's goals better than ladder logic does?

So you know where I'm coming from, I do not do robotics, I do process control, where ladder logic is used extensively. I'm all for ladder logic, but I'm not sure ladder as an end goal in itself is what your school is trying to do.

Dan

 

[sdowns]

To me, ladder logic, belongs in a trade school. But you're not a trade school.

Dan, We try to provide a broad base education that give a student a variety of experiences while promoting interest. For example in one activity in our "robotics class" a student uses a cnc router to cut out a maze designed with CAD software to make a game they mount on pnumatic cylnders. The "thinking process" involved with ladder seems to be aplicaple to a variety of situations beyond the physical PLC?

 

[Ron Beaufort]

in one activity in our "robotics class" a student uses a cnc router to cut out a maze designed with CAD software to make a game they mount on pnumatic cylnders.

now THAT sounds pretty impressive for a high school class ... how much time is involved in getting that project accomplished? ...

 

[sdowns]

Ron, The maze only takes about 8-10 work periods. We have limited equipment so the kids are round robin fashion with a bunch of other projects so it may be a number of weeks until they get that particular project done. Pretty good though that they have to use CAD, CNC, band saw, belt sander, hook up some pneumatics, and it's their own design. I can't take credit for project idea but the kids like it.

 

[SLC_Integrator]

I was asked to help come up with a couple of fun applications to demonstrate what a PLC can do for high school kids at our local tech college.

They use a micrologix 1000 but a small GE PLC (Micro or a Versamax) would work just as well.

The two systems we built in the end where a simple product level/flow mix and separate system using closed clear acrylic tanks of glycol and mineral oil (they have a pretty big gravity difference so they separate nice and quickly, plus one is green and the other is clear so its obvious whats going on) and the coloured ping-pong ball sorting machine.
We found a cheap colour-recognition device from P&F and it was simple to put together for the college.

The idea is the machine has auto mode and manual mode and see if the kids can sort a container of red/green/blue ping pong balls as fast and reliably as the plc can.

Both look and work great!

 

[monkeyhead]

I grew up in a mining community, and the mines dumped a ton of money into my high-school's Vocational Technologies. I loved the programs and they've proved invaluable to me in both my personal and professional life, so it's nice to hear of other schools with these types of programs.

I'd definately stick with the PLC. It's a general purpose automation tool, and it introduces boolean concepts quite well. I think you'll be able to give the kids a lot more options to explore with this route. Far more flexible than specialized robotics equipment and software.

Buying 10 point Allen Bradley "Micrologix 1000" plcs and Downloading the free version of the programming software that is compatible with this controller (and this controller only) could be a cheap solution to your problem.

 

[Peter Nachtwey]

And so you have a PLC. Then what?

A PLC with 10 inputs and outputs that aren't connected to anything or do anything isn't very exciting. The cost of connecting the PLC to outputs and inputs must be added to the cost of the PLC. A couple of the inputs should be analog so something like Ron Beaufort's Hotrod temperature PID system can be made.

 

[CowDung]

I would agree that including analog I/O would be beneficial. A creative teacher should be able to find a multitude of fairly inexpensive things to hook up to a PLC that will inspire projects that are interesting to the students--model trains, aquarium pumps, motors, solonoid valves, prox switches, etc. A couple of more expensive items would include level/temperature transmitters, but even those could be had for a couple hundred dollars (and probably less for schools/educators).

I strongly disagree with the idea that PLCs and ladder logic belong only in tech schools. They can provide real benefit to any HS student by developing problem solving and basic engineering skills. Even the exercise of translating a 4-20 mA level signal into gallons or inches of water is a valuable thing for HS kids to know. It's always nice to have a real use for those formulas they are forced to memorize in their math and physics classes...