Can anyone suggest a mechanism whereby (gracefully) re-booting the a MP277 8" would cause two INT recipe values to be written as zero in memory on the cpu315 ?
Created by: mynamesnotnick at: 6/19/2009 9:38 AM (3 Replies)
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| 6/19/2009 9:38 AM | |
Joined: 10/10/2007 Last visit: 12/5/2024 Posts: 20 Rating:
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A few days ago I had a repeat of the same issue. Fortunately this time two things were different; the operator was vigilant and immediately alerted me to the zero values, so I could reset them to the intended values. Secondly, this time it became obvious that it was cycling the power on the hmi that somehow caused the incorrect values to be written. Can anyone suggest a mechanism whereby (gracefully) re-booting the a MP277 8" would cause two INT recipe values to be written as zero in memory on the cpu315 ? The default values in the recipe definition are 600 and 1100. The only other clue I can offer is that the hmi was extremely slow to respond the keystrokes, for the first 5-10 minutes after re-boot, almost athough it was not polling the touchscreen for events fast enough (I still have no joy on that mystery, either).
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Last edited by: CS Moderator at: 6/19/2009 2:49 PMnew subject after splitting. for more information about the origin-thread go to /tf/WW/en/Posts/30345#top |
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| 6/19/2009 2:00 PM | |
Joined: 1/29/2006 Last visit: 3/10/2025 Posts: 449 Rating:
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Hi again! I dont know, how reboot of MP277 affects the recipe handling. In my axperience, not at all. I would say, that something is "rotten" in your panel or in communication between panel and CPU. I would take following steps: 1. In CPU, I would insert a small program, which would simply controll critical recipe values. If they are outside of expected (=safe) limits, I would first limit them and then program a proper action (Warning, stop of machine, anything like that,....) and try to find out exactly, what causes this behaveour, if possible. I would also generate a message at every change of recipe value (in CPU!), so that you can later see, when does it happen.... 2. I would check the behaveour of your panel, all recipe settings, and also investigate this slow respond. I have seen, that you have had a discussion allready about this problem: /tf/WW/en/Posts/29689 Maybe you shold recompile your project and also download firmware on panel? I remember, that we have had the same problem (very slow responce)once, after conversion of older ProTool-Pro project in to WinCC flex project. It turned out, that problem was in acquisition cycle of some bigger array variables! have fun! uel123 |
| 6/22/2009 2:54 PM | |
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Joined: 10/10/2007 Last visit: 12/5/2024 Posts: 20 Rating:
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thanks uel123 for your helpful suggestions. I have already put in place a program to detect and recover from 'unsafe' zero values....but how far should I go ? Should I assume that any value in the cpu can randomly be overwritten by a rogue hmi ? It is disappointing to pay such a premium for these products, yet suffer terrible performance and eratic behaviour.  I have re-compiled and re-downloaded the program several times since the problem first occurred. The latest one was on Sunday morning when the screen lost the admin username or password, so operators could not edit recipes. |
| 8/13/2009 12:51 PM | |
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Posts: 218 Rating:
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Hi, As for resetting the INT's on reboot: Create a tag linking to the Always_1 bit. Create it if you don't have it. On this tag you use the event: Change Value. Function to be used should be: SetValue. Tag(Out) should be the INT's and Value should be 0 This function will only be executed at the moment when the Panel establishes connection to the PLC. Thus on a reboot. As for rogue hmi writing to the PLC: The hmi will only write to the PLC when you/operator/script give the explicit order to write. Even reading data is done with explicit order, read configuration. If you suspect the panel is faulty, then please contact your distributor to see what can be done. That being said, if you have tags resetting to 0 on a reboot, you need to inspect the configuration of the hmi. What can access those tags and where does it get its data. Never have I seen a hmi randomly reset data and never have I heard of it happening, which makes me believe your configuration of the hmi doesn't include shutdown/reboot handling. Hope this helps Jeebs |
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