PLC Progamming - How hard is it to learn?

  1. PLC Progamming -- How hard is it to learn?

    Hi everyone,

    I have an internship this summer and I'm hoping to convince them to let me independently study PLC progamming. How hard is it to pick up on your own?

    extra info: I've taking C sharp and C++ progamming classes in college

  2. jcsd
  3. Mark44

    Staff: Mentor

    What is PLC? The first programming class I ever took (about 40 years ago) was PL/C, which is related to PL/1. I don't believe that anyone is still writing code in these languages.

  4. Do a google search for "ladder logic". Knowledge of machine electrical prints would be helpful for you. However, the term PLC (programmable logic controller) may be loosely applied and the actual syntax of the language will vary depending on the manufacturer.
  5. PLC programming is easy to learn, a top level book is "Automating manufacturing systems" with PLC's by Hugh Jacks. Highly worth every penny. You can get some free software for the smart relays with certain companies. Zelio soft 2 is downloadable for free for the Sneider electric website. However the free versions is limited in instructions compared to the full blown main products. I do PLC programming for a living so I can certainly help you with your programming. Automation direct also has an inexpensive product line.

    Naturally in the US the top PLC software is AB., there picosoft smart relay programming lanq is fairly inexpensive, however their SLC 500 software runs around 2 grand. You can also study any plc software by downloading the instruction set manuals, however its best to start with an inexpensive smart relay.

    In Europe the top lanq is STEP 7, other lanquages is Omrons CX-Programmer. I can't recall Mitsibushi's I've only dealt with the ones I mentioned primarily
    CalcNerd likes this.
  6. had to dig up the book, another good book is Programmable Controllers
    Theory and Implementation by L.A. Bryan, E.A. Bryan

    Unless you want to get into Robotics, I would start with those two, but if you want to get started in robotics another Hugh Jack book is Integration and Automation of Manufacturing Systems, though this one is far more extensive in system integration, of which PLC's is merely 1 or two chapters.

    here is a code I recently wrote in Zelio soft I printed it as a PDF so you can view it.

    It will give you some idea on the relay logic structure, as mentioned every manufacturer of PLC's has its own language, however they are all based on relay ladder logic, or they can use SFC sequential function chart, or FBC function block control. Start with relay logic though

    Attached Files:

    Last edited: Apr 29, 2014

  8. WOW! Thanks for your replies! They were very informative and I do plan on picking up those books. I'll be sure to contact you in the future if I have questions. Are you logged into Physics Forums often
  9. yes, I'm here often. One other piece of advise. relay logic is essentially Boolean expressions. It uses NO and NC contacts. line one on that pdf is the same as , start and (not stop)= (set start latch) notice how start and stop are placed on the same rung.

    start--------(not stop)--------------(set start latch),,, used to handle a momentary start switch
    for an OR statement

    reset-------------------------------------------------------(deactivate start latch)
    stop ----

    the layout where one rung is below the other, is how OR statements are performed. The output is always the far right, and can only be set in an assigned column. see rung 7 pump1,pump2 are layed out as an or statement. the full statement is (pump1 or pump2) and (not flow fault)-----run pump

    keep in mind I used the label names not the input/output designation, as those are assigned in the tables on this PLC model.

    so study switch terminology and the terms normally opened and normally closed, you can pick up several relays to practice physically wiring them up in different and or configurations.
    Last edited: Apr 29, 2014
  10. PLC Hardware

    PLC programming is easier to learn when you have the hardware to use. I know that we get some reconditioned Allen Bradley (Rockwell Automation) PLCs from Tek Supply. The website is at You can get a complete system there and use your laptop. They also have most of the other PLC brands. Also you should check out the site and take advantage of the forums there. There are thousands of experienced members that belong to that site and they are always willing to give advice. Good luck!
  11. lol I haven't been to that site in ages, I tend to go to Not to say there is any pros and cons between one or the other. Both are as far as I'm concerned are equally good
  12. dlgoff likes this.
  13. dlgoff

    dlgoff 3,045
    Science Advisor
    Gold Member
    2014 Award

    This application from your link is cool; being I'm a home coffee connoisseur.

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