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Steady output if conditions are met, flash if not..?

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  • Steady output if conditions are met, flash if not..?

    I'm configuring a P1-540 and a C-More EA3 for a CIP skid in a brewery. I am trying to add a bit of safety to the machine, so the pump only runs when certain conditions are met. It's pumping 180 degree caustic soda with a 15hp 460v pump, so safety is imperative.

    Pump switch off = pump indicator off, pump off
    Pump Switch on, conditions not met = pump indicator flashing, pump off
    Pump switch on, conditions met = pump indicator steady, pump on.

    What I can't figure out, is an effective OR or ELSE statement. Like, actual logic items.

    I'm having a hell of a time achieving this. Can someone help?

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  • #2
    Your issue is you have "Pump Status" as an output, twice. In PLC logic, last instance of this output wins.

    Change your "Pump Status" flasher output to a new tag titled, "Pump Status Flasher."

    Next, create a third rung, with an OR of two NO contacts. One NO contact will be "Pump," the second NO contact will be, "Pump Status Flasher," and your output will be, "Pump Status."

    This should get you what you're expecting; a flashing light when conditions are not met, and a steady when conditions are right.
    Why worry? If you've done the best you can, worrying won't make it any better

    - Walt Disney

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    • #3
      That worked, thank you!

      Side note, I've been using the Do-More Simulator. Does Productivity Suite have a simulator - it's getting frustrating testing at home in a separate program.

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      • #4
        Unfortunately, no. The only other option is purchasing the starter kit. It's what I use to train my colleagues. $298.00 is not bad. Link HERE.


        Edit: On your rung 1, eliminate the output "pump status" ORed with "pump" and in rung 2 change the NO "pump status" to "pump."
        Last edited by Todd Dice; 10-26-2019, 12:48 PM.
        Why worry? If you've done the best you can, worrying won't make it any better

        - Walt Disney

        Comment


        • #5
          Originally posted by craigmurphy View Post
          Side note, I've been using the Do-More Simulator. Does Productivity Suite have a simulator - it's getting frustrating testing at home in a separate program.

          Click image for larger version

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Views:	171
Size:	43.3 KB
ID:	126154
          I want to believe that if we all scream loud enough, it's something they'll consider adding.

          For now, I have a P1K / 08SIM / 15CDD1, powered from a USB port on my laptop that I use for simulating. Of course, you can't simulate the entire program usually, you have to break it down in to sections, but it get's me by, albeit in a frustrating way.

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          • #6
            Originally posted by Brandon_ View Post

            I want to believe that if we all scream loud enough, it's something they'll consider adding.

            For now, I have a P1K / 08SIM / 15CDD1, powered from a USB port on my laptop that I use for simulating. Of course, you can't simulate the entire program usually, you have to break it down in to sections, but it get's me by, albeit in a frustrating way.
            One *almost* excellent thing that the P-series has is Debug Mode.
            if debug mode did not require a STOP-Mode, I would use it more.

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            • #7
              Originally posted by Brandon_ View Post

              I want to believe that if we all scream loud enough, it's something they'll consider adding.

              For now, I have a P1K / 08SIM / 15CDD1, powered from a USB port on my laptop that I use for simulating. Of course, you can't simulate the entire program usually, you have to break it down in to sections, but it get's me by, albeit in a frustrating way.
              I'd love to have a simulator as well, but with the P1K, and some creative aliasing, I can simulate all the I/O with a Data View window...

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              • #8
                Originally posted by genebond View Post

                I'd love to have a simulator as well, but with the P1K, and some creative aliasing, I can simulate all the I/O with a Data View window...
                I remember going out to dinner with some of the Productivity team ~4 years ago, asking about a simulator and them looking at me like I had a 3rd eye. "Why would you want a simulator?"

                Right now I'm sitting at my hotel in Indianapolis and I would really like to test a theory on some code that is floating around in my head. That's why.

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                • #9
                  Gotcha.

                  I live in Indy. Want to borrow my P1K? I'm on a different project for a few days PM Me...

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                  • #10
                    Originally posted by genebond View Post
                    Gotcha.

                    I live in Indy. Want to borrow my P1K? I'm on a different project for a few days PM Me...
                    I appreciate the offer, but all is well. I have a few dozen P1K and P2K back at my clients facility that I'm working at this week. I have a USB powered P1K that I usually have with me, but I left it at their facility last night.

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                    • #11
                      New problem related to my original post - I have a few screens on C-More, one for Automatic operation, and one for manual, specifically. I have rungs for manual operation (pretty basic - NOE switches, with Toggle coil outputs (2, both for the indicator and for the various devices). One rung per switch, one subrung on each for the indicator. Works great. As soon as I enable my "automatic mode" rung (there's many subrungs, controlling many various devices based on time, temp, various DI, etc), whichever rung is on the bottom, wins.

                      What's best practice for when you want to control an output in a couple different ways (like on a manual and an automatic screen?)

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                      • #12
                        A couple issues come to mind:
                        1. Safety
                        2. Output maintenance when switching between Man/Auto or Auto/Man

                        How safe is this? I am not an FMEA guy, so risk assessment is not something that I intend to do publicly.
                        Do the outputs need to be maintained when switching modes, or should they always go to a default state?

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                        • #13
                          I ended up using internal tags for manual and auto triggers, then outputting to the actual coils with a manual/auto internal tag OR.

                          To answer your question, it's designed to keep state between manual and auto screens. E-stop in place that both resets the outputs in PLC, and also cuts 24v and air to solenoids. It's pretty redundant from a safety perspective - we're working with lots of juice, nasty chemicals, and very hot water.

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