I need help with this ladder logic question

Discussion in 'Homework Help' started by NickH303030, Apr 15, 2018.

  1. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    This is the question:

    Use the Door Simulator in Logix Pro to implement a program that will automate the garage door opening and closing process. The sequence of operation is as follows:

    • Initially, the garage is closed
    • When the OPEN button is momentarily depressed, the garage door will open
    • When the door reaches the top limit switch, it will pause for 10 seconds, and then automatically close
    • The OPEN indicator light will activate only while the door is traveling upward
    • The SHUT indicator light will activate only while the door is traveling downward

    My attempt is posted. I can’t get it to function properly.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    What are the respective I/O labels?
    Max.
     
  3. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    This is how I originally drew it up
     
  4. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    This is a screenshot of the door simulator from the program.
     
  5. MaxHeadRoom

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    Jul 18, 2013
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    First what results or symptoms do you get when the program operates?
    Max.
     
  6. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    It
     
  7. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    It doesn’t automatically close after 10 seconds and also it closes when it’s supposed to open and vice versa. The motor stalls as well.
     
  8. MaxHeadRoom

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    Jul 18, 2013
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    One usual practice is to interlock both motor outputs, i.e. place Motor Open output in Motor Close output string and vice-versa.
    As N/C contact for e.g.
    Max.
     
  9. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    Ok I’ll try that. Also should I include I:1/3 and I:1/4 based on the door picture I posted above?
     
  10. MaxHeadRoom

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    Jul 18, 2013
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    I thought LS I:1/0 and I:1/1 were the up/down L.S's?
    Max.
     
  11. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    I:1/0 is the open
    I:1/1 is the close
    I:1/2 is the stop

    3 and 4 are the limit switches. I’m not sure how to implement them
     
  12. MaxHeadRoom

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    Jul 18, 2013
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    Ah I see, you showed them as L.S. in your original listing, not P.B's , and only one P.B. but so just I am not sure what O:2/02 Ajar is?
    If It closes automatically, I assume the stop and close P.B.'s are an override or alternative operation of the door procedure?
    Max.
     
  13. NickH303030

    Thread Starter New Member

    Apr 15, 2018
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    An override sounds exactly right. The door needs to automatically close so for this program we won’t need to press the shut or close buttons. We just need the door to start the process when the open button is pushed and then when it starts shutting the shut light needs to come on.
     
  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The logic for the IND lights appears wrong, the description shows the light are on only when motor is moving, either up or down.
    You have the respective up/dwn L.S. turning the lamp on.
    While the door is in transit either up or dwn, the L.S.'s will be in the same state.
    Hint, use the motor outputs.
    Max.
     
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