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firebird0095

1734 Point IO After Power Outage....

6 posts in this topic

Well I am back to ask the experts and see if anyone else has had a similar issue as I am not having any luck fixing this one. I have a completely separate (physical and subnet) ethernet for the machines. I have a compactlogix controller that is essentially a central control and monitor for some simple machines and building utilities and the I use Point IO spread out all over the building to interface with about 30 different pieces of equipment through three main drops with 1734-aent adapters. There is a Panelview Plus in the mix also to display everything that is going on. The problem is that after a power outage - either brown out or completely out - it all seems to lock up. The panelview will display numbers, but they are unchanging. The PV will sometimes have an error message about not being able to connect to the PLC. The outputs on my drop points are all off and stay off even though they should be cycling on and off. I have put battery backups on everything including switches to try to stop it, but it still gets messed up now and then. I am using the watchdog timer in the main controller, but I have not found a similar option for my drop points. Is there any way to force them to internally reset after the power comes back on? Has anyone else had this?

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Not sure I have enough info to make an educated guess, but is it related to the MSG commands getting "stuck"? That said, probably going to delve into the problem with some extensive troubleshooting. I have several mid sized 1734 installs and don't recall seeing this at any of my brown outs. Lots of good knowledge here in the forum to help

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After the power outage what are the LED's doing on the front of you PLC, Network adapter in the PLC rack and also the LED's on the 1734 adapters. Also when you go online with the PLC do you have any errors on the adapters, Are the network switches ok after the power outage or are the faulted. There could be a number of issues here so more info is needed to help you.

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The front of the PLC shows an IO error. The Ethernet is integrated in the processor on the Compact Logix, but the lights are blinking and showing traffic on the line. The switches all come right back on as normal. I never get enough time when there is actually a problem to really troubleshoot this, so I am going to simulate the condition as soon as possible when production is not running. The "fix" for it is to power everything down and then back up again and it works. There seems to be something different about it when the whole building goes out.

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"The front of the PLC shows an IO error." I would imagine this is the key indicator. I would think that the point I/O can't re-establish the connection to the PLC "Master". I think it will be a network communication issue. Just my two cents.

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I had a similar problem turns out I forgot to set up a subnet mask on one of the IO Adapters after fixing this there was no more problem

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