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Help with first program please

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  • #16
    A "proper" e-stop has to be external to any Automation direct PLC, none are safety rated (a safety rated PLC is a rare beast)
    If your application does not present any personnel safety issuers and you just want to stop it when/if someone presses a button you could just have another contact(s) that disables rung(s) for whatever you want off.
    A "proper" e-stop will need likely need to remove power from the stepper drive.

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    • #17
      Originally posted by Tinker View Post

      ST0 is only on for a singe scan ("there can only be one" [first scan]), and while experience has show that one AXCONFIG can execute in a single scan, an asynchronous instruction in principal could take more than a single scan. I have had failures trying to configure 3 axes on the first scan, using a stage might well be better.
      AXCONFIG should latch the input state, so only a single scan is required. If you have had cases of a failure and can duplicate it, I'd like to know how.

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      • #18
        Originally posted by KevinB View Post
        Thanks for the new program also. You have some stuff there that I don't understand yet, so I'll study more and try your program once it's all wired up. Does the addition of the Prox_Went_On bit eliminate the need for the RowPresentProx to be cleard before the conveyor comes to a stop?
        The Prox_Went_On actually doesnt do anything. I think I was going to make it do something in there but then decided against it and forgot to take the bit out. The bit just follows X3 anyway so its redundant even if I had decided to add more behavior to the program.

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        • #19
          Okay thanks again guys, I've been working on wiring and will get back to the program once everything is connected. For the e-stop, I ended up using a control power relay that kills power to the PLC and disbles the stepper drive. That should be plenty good.

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          • #20
            Well it's all working using a slightly tweaked version of what Mike N posted. There's one more thing I'd like to change though. Currently, pressing the stop button while the timer is running has no effect. I think I need to use an interrupt but not sure the correct way to do it. Can anyone tell me what needs to change?

            Also, how do you make a nice pdf of the ladder logic like what you posted Mike?

            Thanks,
            Kevin

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            • #21
              Okay I guess you guys thought that the above question was too stupid to answer and I'd figure it out on my own, and I guess it was, and I did. I jumpered the Stop input to the next available input, used that one for the the interrupt to set a new bit, and checked that bit before re-starting. I don't know if that's the "right" way to do it, but it worked.

              Here's a 46 second video of the completed project. Thanks again for the help.
              Kevin

              https://www.youtube.com/watch?v=Lmw6zbRlYyo

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              • #22
                wrong post :-\
                Last edited by franji1; 01-13-2020, 09:54 AM.
                There are 10 kinds of people in this world, those who know binary, and those who do not.

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                • #23
                  Originally posted by KevinB View Post
                  Well it's all working using a slightly tweaked version of what Mike N posted. There's one more thing I'd like to change though. Currently, pressing the stop button while the timer is running has no effect. I think I need to use an interrupt but not sure the correct way to do it. Can anyone tell me what needs to change?

                  Also, how do you make a nice pdf of the ladder logic like what you posted Mike?

                  Thanks,
                  Kevin
                  I just took a screenshot of my desktop and trimmed the image to only show the ladder logic. From there you can print as PDF if you need to.

                  Sounds like you already got the stop working correctly, but as for stop button when looking at my code, it looks like you could add a stop contact to line 8 so that it resets C3. That would turn off the timer and y4 output.

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