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  • HMI / PLC Timeout errors

    I use DL06s (initially D0-06DR, more recently D0-06DR-D) with EZ-Automation EZD-T6C-S panels. (We began with ADC EZ-S6M-F panels, then switched to the same panel from EZ-Automation, then switched to the ‘Durapanel’ in 2010.) Communication between the PLC and the panel is via a short RS-232 cable in Port 2.

    I get a lot of PLC COMMUNICATION TIMEOUT messages on the panel. We’ve always seen these, but it seems to be getting worse. And it seems that sometimes I’m missing touches on the screen as a result. We run at the comm line at 38 kbaud. We did some very uncontrolled experiments with lower baud rates, with no obvious effect.

    I thought that maybe the problem was that the PLC was in a loop somewhere, that the CPU got very busy and started ignoring serial i/o requests. But my maximum scan time is typically in the 16-18 msec range, and that doesn’t seem too bad.

    Wild speculation: I have an intermittent bug in my code that seems to be getting worse. I believe that the bug is related to the fact that I sometimes rely on the panel to tell me what screen it is displaying, and I suspect that the screen number doesn’t get updated quickly enough. I put in a one-line hack that I think eliminates that problem, but the timeout errors persist.

    All of this has gone on through at least half a dozen PLCs and touchscreens – it’s not just a simple one-off defective component.

    I would be grateful for any suggestions of how to troubleshoot this, and/or how to improve the communication success between these devices!

    Puzzled,

    Paul in SE Wisconsin


  • #2
    First off, go to the system screen and see what errors are actually being reported. Sometimes the system screen will tell you more than the alarm banner message.

    RS-232 is a ground referenced signal. The panel and PLC need to be grounded at the same point to eliminate ground potential differences.

    Make sure that the panel power as well as the communications cable is ran as far away from other wires and devices as possible to try to help eliminate interference.

    Is the communication cable shielded? If not then you need to be using a shielded cable with the shield grounded at one end only.

    Lastly, if you made your own cable, make sure that all solder joints are solid and that any crimp ends are solid as well.
    If you have an urgent issue, please contact AutomationDirect's Technical Support team.

    AutomationDirect.com Technical Support: 1(800) 633-0405 or (770) 844-4200 Email Tech Support

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    • #3
      Thanks for the prompt response. I have no idea what you're referring to when you say, "First off, go to the system screen and see what errors are actually being reported." I'm curious to know...

      I seem to have resolved the issues -- both the comm errors and the seeming program bug. I installed the most current firmware into the panel, and I can no longer cause either problem. That's frustrating, on the one hand -- it would be a lovely gesture if EZ-Automation would ship new panels with the most current firmware already installed -- but it falls well within the scope of "all's well that ends well."

      Thank you again for your help!

      Paul in WI

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      • #4
        Originally posted by clintonp View Post
        I have no idea what you're referring to when you say, "First off, go to the system screen and see what errors are actually being reported." I'm curious to know...
        It's magic... well almost...

        On a CMORE screen, pressing and holding the very upper left corner of the screen will bring up the system screen. On the EZ-touch that AD used to sell, it was two corners, I believe the right two, but it's been a few years. Check the documentaion on your panel for where to tap the Magic Wand.


        EDIT see page 41 (50 of 93) of the hardware user manual to enter the system screen...
        http://flash.ezautomation.net/downlo...e%20Manual.pdf

        It's the upper and lower left corners to enter the system screen, although I don't see anything about an "Error" list like the CMORE has.
        Last edited by Bob S BN; 04-24-2012, 12:44 PM.
        Bob

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        • #5
          Thanks, Bob -- perhaps that's what ADC App Assist was referring to. It's n/a on my screen. As far as I know, there is no such feature on the EZD ('Durapanel') screens. You can poke 1, 2, 3, or all 4 corners, to no avail. At least, that's been my experience. If EZ-Automation every prints a new manual, that explicitly references the existence of these screens, perhaps they'll mention that detail. Perhaps I shoulld be looking at C-MORE. But I think that I'm recalling that low end panels, like the EA7-T6CL-R (which is comparable to what I'm using, price-wise) don't retain their programs through a power loss. Can't have that...

          Thanks again,

          Paul


          Originally posted by Bob S BN View Post
          It's magic... well almost...


          On a CMORE screen, pressing and holding the very upper left corner of the screen will bring up the system screen. On the EZ-touch that AD used to sell, it was two corners, I believe the right two, but it's been a few years. Check the documentaion on your panel for where to tap the Magic Wand.


          EDIT see page 41 (50 of 93) of the hardware user manual to enter the system screen...
          http://flash.ezautomation.net/downlo...e%20Manual.pdf

          It's the upper and lower left corners to enter the system screen, although I don't see anything about an "Error" list like the CMORE has.

          Comment



          • #6
            I didn't know any Cmores had issues with losing programming on power loss. It's never happened here anyway.

            And I would have thought that hardware manual would be for your unit. I pasted your model number in at the EZ website, it listed the model number, and showed that link to the manual. Are you sure you're only holding the corner touch cells on the left side, and not any next to them?
            Last edited by Bob S BN; 04-24-2012, 02:39 PM.
            Bob

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            • #7
              Originally posted by Bob S BN View Post
              Are you sure you're only holding the corner touch cells on the left side, and not any next to them?
              The three words my wife most loves to hear: "I was wrong."

              I'm used to the older panels, with the large (roughly 1/2" x 1/2") cells. This panel has twice the cell density. Carefully touch only the corner cells, and up pop the setup screens.

              I still don't see anything there that would be useful for error identification...

              Thanks,

              Paul

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              • #8
                It may not be there on the newer ones. I haven't seen one is years so I am a little out of date with respect to their products.
                If you have an urgent issue, please contact AutomationDirect's Technical Support team.

                AutomationDirect.com Technical Support: 1(800) 633-0405 or (770) 844-4200 Email Tech Support

                Comment



                • #9
                  Hello clintonp;
                  We had similar problems with comm errors between a D006 and a touch screen, and it turned out to be mostly caused by solenoids sending transient voltage spikes back into the PLC. We fixed it by installing interposing relays and some 120VAC transorb modules.
                  We still had intermittent problems until we brought the grounds from the PLC and touch screen to the same lug, and made sure the comm cable was routed well away from all power cables.
                  Before all these changes, the system would lose comm for as much as a few seconds about every minute or so, and now it almost never happens.
                  Hope this helps,
                  Speakerman.
                  "Analog" is still binary, it's just at molecular resolution!

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                  • #10
                    EZ Automation / DL06 Communications Timeout

                    Thanks to all who have replied.

                    Apparently the problem is all about the firmware in the screen. EZ Automation puts a piece of paper in the box with their screens that says, in essence, "Don't forget to load the most recent firmware into the screen." It would be nice if they would ship with the current firmware already in place. Updating the firmware solved the problem. I don't know how we missed that...

                    Paul

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