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  • Timer Zeros

    Looking for other ways to deal with "timer.current=0" in the Psuite. Currently if I'm doing an off-delay I have an NO contact "timer.less" as well as a CMP contact "timer.current>0". IIRC Do-More has a timer.timing tag which would work for many applications. Is there a better/faster way to handle this situation? Thanks

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  • #2
    The timers are not timing unless the "Blow Process Latch" is on, and the outputs cannot be on unless the same latch is on. So, if the latch is on the timer will never be 0 since you are already counting up. Do you really need to have the compare for greater than 0 in your output rungs then? As those lines will never be true when the timer is 0.


    Also, if you never plan to use the time down input, why not use a simple timer instead?
    Last edited by MikeN; 05-11-2018, 04:43 PM.

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    • #3
      Have you looked at the Drum or Sequencer instructions?

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      • #4
        Originally posted by MikeN View Post
        The timers are not timing unless the "Blow Process Latch" is on, and the outputs cannot be on unless the same latch is on. So, if the latch is on the timer will never be 0 since you are already counting up. Do you really need to have the compare for greater than 0 in your output rungs then? As those lines will never be true when the timer is 0.


        Also, if you never plan to use the time down input, why not use a simple timer instead?
        Your comment made me rethink things because these outputs need to happen in sequence. Receiver pumps down and then its line can be blown(product ends up in the MW Vat), MW vat pumps down and then its line can be blown. Since MW vat holds a lot and takes longer to pump down, I have it start pumping when receiver is pumping & blowing down versus waiting for them so it speeds things up.

        Anyways, I simply removed the process latch contact from both of the blowdown rungs and replaced it with timer.greater for their respective pumps which eliminated the need for compare greater than zero because now they cannot be true until the pumps are done.

        As far as timers go, I guess its just preference due to working with an HMI and not wanting to deal with working in 1/100 seconds. Easier than adding math instructions to convert I think, but could be wrong.


        Thanks


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        • #5
          Originally posted by LWgreys View Post
          Have you looked at the Drum or Sequencer instructions?
          I have not used either of those, but I am working on another program right now that I think those instructions may be useful for as well. Do you have any examples you'd care to share? Thanks.

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          • #6
            Just went in and redid an existing program with a sequencer to test my understanding of it. Took that program from 25+ rungs, 100+ instructions and 12 timers down to 5 rungs, 18 instructions and zero timers. Cleared out a pile of tag names as well. Works great, I'll be doing the same to the blowdown one shown above.

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            • #7
              The Sequencer is your friend!
              - J. Payne
              "Controls make the world go round"

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              • #8
                Sorry I have not been on-line for a while, but I'm sure glad I steered you in the right direction.

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