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Who can remember the ground work for the PLC?

I was thinking that the old Cardlok Logic racks would be a good teaching tool to help students learn both logic and wiring systems. This would also give them a better understanding of the basics of programming. Does anybody remember going through the pages of logic and troubleshooting conditions of a large production line from the gate all the way to the remote coils and actuators of a hydraulic ram or an input from a flip-flop back to a pressure switch.

I wanted to hear what your thoughts were on this old hard wired electronic control logic system, Allen Bradley Cardlok System??

If might be a challenge to find some of the old racks to build some trainers.

Thanks
-Pat
Feel free to also contact me off list it you would prefer pkeblaiti (at) LTU (d0t) edu

Hi there,

The method of PLC training I use is to start by explaining the basics of what a electromagnet is and how it is build. The next step is to explain the workings of a normal 12VDC relay and how the base is connected to the contacts and how the numbering works. Thereafter we start with a simple stop start relay ladder logic design on paper. Once this is done the student builds the circuit from the drawing to get a feel for the whole thing in practice. After that he needs to design some relay logic circuits himself and build one or two more with actual wire and relays and timers. Once he have a thorough understanding of relay logic we convert all the drawings directly into plc ladder logic so that he can see that there is no difference between what he have done and learned so far about relays and PLC programming. After they see this the enthusiasm normally runs very high and they start to believe that they might actually be able to do programming and that it is not as complicated as they though it would be.

I used to "program" the cardlok systems for the company I worked for. When we started converting to PLCs (Modicon and AB) I thought that this would be a piece of cake!

I remember that you definitely wanted to double check the data sheets that came with the logic cards to make sure you wired them correctly, otherwise you could release a lot of smoke! You might have a hard time finding the termi-point gun and the terminals for the back of the rack.