stop button won't work in batch project logixpro

amhd90

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Join Date
Sep 2015
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Beirut
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Why in this code that I just did, my stop button does not work properly. I am solving the batch simulator on logixpro

LadderRungs.jpg
 
When you say "stop button does not work properly" what exactly do you want it to do?
What is it currently doing?

When you ask these questions and look at the code we can see alter the logic.

Regards,
 
Agreed change stop button. Looking at that Im not sure how any of that could work starting at line 0 the way it is. How would line one be able to latch in?
 
In a real world application, you are correct to program a XIC because the field stop button should also be a N.C. contact. That way it would detect a broken wire in the stop circuit.
 
no XIO

In a real world application, you are correct to program a XIC because the field stop button should also be a N.C. contact. That way it would detect a broken wire in the stop circuit.

No, XIO NC contact brings in true- XIO go true then - continue on
 
In LogixPro the stop button, is normally closed that's why I used it as XIO, to stop all the process when it is clicked, so any help ?
 
If your Stop PB is NC, then your code is correct. It would have to NOT be pushed & no broken wire to allow the output to energize.

If the output does come on, then the current is flowing - if when you push the Stop it does not turn off the output see if the XIC drops when online, if yes see if the ladder is being scanned (maybe a JSR is not being triggered); if the XIC is not dropping maybe there's a short (or jumper) in the wiring bypassing the Stop NC contacts.
 
can you be more specific ? I am new to all of this, if you can tell me step by step how to correct it, I don't wont to see ready made solution of this exercise I want to resolve it by my own.
 
1. At the beginning of your main routine add a line turning OFF Test_Bit_45 every scan

2. In the routine just after your motor control line add a check of the Stop button input & turn ON Test_Bit_45 if on.

A. If Test_Bit_45 does not come on then the routine is not being scanned

B. If Test_Bit_45 is always on, even when you press the Stop PB, then there is a wiring problem bypassing the Stop button NC contact

C. If Test_Bit_45 responds correctly, but your motor output stays on, then search your program for all occurrences of the motor output & see if it is controlled a second time later in your program

D. If Test_Bit_45 responds correctly & the motor output responds correctly while monitoring online, then the PLC output may be faulty, or the wiring in the panel is wrong.

EDIT: Didn't notice the latch Steve Bailey just noticed while I was typing, which means response "C" needs modified.

Also, I would not use a latched output to control a motor. You would have to add check if the MCR was off, E-Stop was activated, motor OLR was tripped, Tank level OK, safety covers closed, First Scan, etc. & unlatch it. I only use latched bits on items I want the PLC to remember if the power or Run mode gets cycled & not controlled outputs.

Test_Bit_45.jpg
 
Last edited:

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