Basic PLC ladder logic HELP!

Discussion in 'Digital Circuit Design' started by tippytoejoe, Oct 2, 2011.

  1. tippytoejoe

    Thread Starter New Member

    Oct 2, 2011
    1
    0
    Can someone help me create the ladder logic? This goes way beyond my minimal knowledge of PLCs.

    assignment: Design and develop a PLC welding system to achieve the following requirements.

    • conveyor C1 activates assembly station AS1
    • The welding stations WS2, WS3, and WS4 are turned on by assembly station AS1
    • The welding stations turn on the inspection station IS5
    The output of conveyor C1 activates the welding stations in parallel.
    When the welds are completed, manual switches could be triggered to show that each welding process is completed.
    Timers could also be built in to simulate the welding process etc.
    Next the inspection station is triggered and serparate outputs indicate good welds or defective welds.

    AS1 and IS1: 1 second
    WS2, WS3, WS4: 3 seconds
     
  2. williamj

    Active Member

    Sep 3, 2009
    180
    32
    ttjoe,

    Having just brief exposure with plc's, I'm not really familiar with their workings but I can assist in the basic ladder logic if you'd like.

    The work stations themselves do not necessarily trigger the next work station. In all likely-hood the individual work stations are triggered by the approaching assembly on the conveyor by sensors located at the individual work stations for just that purpose.


    1. assembly set on conveyor and conveyor is initialized
    2. assembly approaches station one (S1)
    3. S1 goes through its program and re-initializes conveyor moving assembly to S2
    4. assembly approaches S2
    5. S2 goes through its program and re-initializes conveyor moving assembly to S3

    And so on and so on. All you need to do is figure out the circuit once and then use it repeatedly for each work station. It will take me a little while to put pencil to paper but once done you can just substitute PLC input/output in place of relays.

    williamj
     
  3. williamj

    Active Member

    Sep 3, 2009
    180
    32
    ttjoe,

    I'm sorry buy I wont be able to help as I planned. My health took a turn south and I was under observation for a couple of days with a change in my head is all fogged up just now and I find I can't concintrate. Hopefully some else here can step in.

    williamj
     
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