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Ladder Logic Problem - output doesn't activate when contactor is closed

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I am trying to modify a PLC program to add extra features but it seems like the basics are confusing me. Im using a Unitronics Vision 570 PLC, programming with VisiLogic OPLC IDE.

I am trying to make a button or a number being higher than another number show / hide a text box but when I run the program and watch the inputs and outputs it seems that the output doesn't turn on. In the picture attached shows the red wire goes to the output but it doesn't turn red.

Ultimately I need a warning sign (text box) to be displayed and latched when an input goes above a user defined level. Is there a simple way to prove the concept before the actual hardware is implemented? Or am I trying to do something that isn't possible?

Thanks,

Jules
 

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  • Ladder Logic1.png
    Ladder Logic1.png
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Hi. Im not familiar with that spesific model and brand.

Is the right side test button normally closed? If yes, that is probably the cause that the light doesn't turn on. Try to remove it.
 
Ok, I've stripped it down to the most basic ladder logic, should this work? the first pic is button unpressed, second is button pressed. I would think that the output should energise unless I'm missing something?
 

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  • Ladder Logic2.png
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You show the same line twice (row 1)
 
Figured out what the problem was - this (new) subroutine wasnt being called or updated with the main logic because I tried putting this logic into the main ladder code and it worked.

Thanks for your suggestions.

Jules
 
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