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How to reset the Alarms triggered after timer has expires

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  • How to reset the Alarms triggered after timer has expires

    Hi Everyone - I need your input - I created an LD program for a 5 Alarm system - The system is divided into 2 parts - 1st part the absent of signal (24v) (input X4) triggers a general Alarm (Y5) and start a timer - 2nd part - After Timer has been completed - I am resetting 3 relays - R11 - to remove the input signal (X4) and this way - allow my equipment to trigger the alarm that originated the problem (Y4). R2 - To reset my general alarm output (Y5) and Y5 - To reset the general output. . What this does it allows my Equip to finish processing by enabling (Y5) and then trigger the true alarm (Y4) - by removing the signal..

    However - What I noticed is that when the timer has elapsed. R11 is energized and removes the signal from Y4 - which is what I want! - My question is in order to reset the timer or restart the program once my Equipment has been fix - Is resetting the PLC - RUN-PRG-RUN is correct (Good Practice) or is it something by code that I can include?

    The Picture shows one alarm - the are 5 of this - basically the same setup w/ different timers - The LD logic is from another PLC (Panasonic -PLC), however I want to do the same on the Click?Click image for larger version

Name:	PLC_Delay_Meg.JPG
Views:	141
Size:	127.1 KB
ID:	122130

    Thanks in advanced for your feedback

  • gesso72
    replied
    Yes - The program is from a Panasonic PLC FP0-C14RS - I posted here - because I want to do the same with a click PLC that I have for my Own training. Thanks for the feedback and responses-

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  • Alexandru
    replied
    you donít need to reset the plc to make the program work.
    if your program can only work if you reset the plc, there is a flaw in your program. There is another way to program the plc to achieve the same result without ever changing run mode.

    set and reset instructions give a quick way to control an output, but then prevent that output from ever getting controlled by a regular coil instruction. Essentially, it is very easy to end up with random behaviour as well as with the need to cycle power in order to eliminate a lock in an output affected by set/reset.

    to close the subject: there is nothing a set/rest can do that a regular energize/deenergize can not. Honestly I donít know why set/reset even exists, because it only brings headaches. I hardly use it, for quick checks in testing only.


    Thank you for the clarifications regarding multiple output on same rung on click plc.

    I donít think the image the initiator posted is a click program. It appears made in a program that allows multiple outputs in series.
    for this reason I wanted to explain why series multiple output is not normal, by using the resemblance to an automation panel.

    I think is more clearer like this:
    1. Imagine the outputs to be three 24vdc coils, powered by the 24vdc power supply.
    2. If three coils are connected series, then each will be powered by only 24/3=8vdc. Not enough to make it work. We can not provide extra voltage.
    3. Ih the three coils are connected parallel, then each coil is powered at 24vdc. With adequate supply it will always work. We can provide enough current.
    Last edited by Alexandru; 04-18-2019, 09:47 AM.

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  • RogerR
    replied
    The click will not allow the out coils in series at the rung end.
    It will allow them to be in parallel at the end so the ladder line can turn on, set, or reset several coils at once.
    To add a coil or contact in parallel, highlight the first coil/contact, press CTRL-Down Arrow.

    Leave a comment:


  • mikeexplorer
    replied
    Originally posted by Alexandru View Post
    Changing plc state from run to stop is not good practice. You should be able to reset the outputs without resetting the plc.
    the rung 3 you donít need to set the y5 because is latched as long as x4 is off.
    the rung 4 is weird. You canít have outputs in series. A plc program resembles an automation cabinet. You wonít see relays energized in series, but only in parallel.
    you accidentally made a program that kind of works.
    the issue that you have is related to the use of set and reset instructions. Those can only clear at plc reset. Try to use coil instructions ( normal output).
    I don't mean to hijack the thread, but in reading your answer above raised some questions with a project I am doing utilizing a Click PLC.

    If you try to put two outputs in series, won't the Click software flag that as not allowed?

    In the program I am writing for this embosser project, I do use set and reset functions because once a condition is detected that is a problem, I want it maintained until the operator clears the problem on the line and presses a reset button. Attached is the program I wrote. The logic must have a means to reset the binary bits, so a PLC reset should not be needed?

    Mike
    Attached Files

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  • gesso72
    replied
    Thanks Roger and Alexandru! - Alex - going by your feedback - You are correct - no need to trigger the coil in series - No sure why I did it this way - Rookie mistake!! So on Rung 3 - Just change my Y5 to a regular coil - Then in reality in Rung 4 I only need to energized R11 in order to trigger Y4(This output will stop the signal to pass through and therefore - Aborting my Equipment!! Thanks for the feedback!! I will try this changes and see if it works

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  • Alexandru
    replied
    Changing plc state from run to stop is not good practice. You should be able to reset the outputs without resetting the plc.
    the rung 3 you donít need to set the y5 because is latched as long as x4 is off.
    the rung 4 is weird. You canít have outputs in series. A plc program resembles an automation cabinet. You wonít see relays energized in series, but only in parallel.
    you accidentally made a program that kind of works.
    the issue that you have is related to the use of set and reset instructions. Those can only clear at plc reset. Try to use coil instructions ( normal output).
    Last edited by Alexandru; 04-17-2019, 10:07 AM.

    Leave a comment:


  • RogerR
    replied
    This logic should not be hard to accomplish on the Click.
    To reset the timer on the Click, the contact that enables the timer can be opened to reset the timer.

    Leave a comment:

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