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Old July 10th, 2016, 11:43 PM   #1
ASF
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PanelView Plus "Timeout Reading" and "Timeout Writing" - battery low

Hi all,

A customer has a PanelView Plus (catalog number 2711P-K4M20D8 ser A) connected to a Micrologix 1400 via Ethernet, which recently started showing low battery alarms, and warning you to replace the battery and check the system date/time, as timestamped data may no longer be accurate. At the same time, it has started displaying timeouts reading to and writing from some variables. The PLC and HMI programs have not changed - the variables still exist in the PLC, and the addressing in the HMI hasn't changed - and it's reading and writing to everything else fine. Add to that, usually the message I expect to see from an incorrect address is "problem reading from..." not "timeout reading from...".

I looked at the ranges that the error describes, and coincidentally - way too coincidentally for my liking - the addresses it refers to are addresses that store the system date and time in the PLC - the program copies the RTC of the PLC into N9:0 through N9:5. I can't see any reason whatsoever that the HMI would all of a sudden stop being able to read N9:0 (but not all the other addresses) just because the battery is low. I mean, the PVP probably doesn't even know what the data represents, it's just numbers, right? But given all of the above, I'm definitely looking at it sideways.

The other offending address range is the "remote display number" and "replace display number" global connections, which is not quite as fishy, but still looks guilty by association.

Obviously, the number one thing to try here is to change the battery - but I'm just wondering if anyone can shed any light on this highly suspicious coincidence before I do that?
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Old July 11th, 2016, 01:02 AM   #2
ASF
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OK, so on further investigation, I've been misled - the PVP isn't communicating with the PLC at all. They powered it down and back up, and those first error messages are because the PVP tries to read/write the screen number and date and time at startup. They told me that the rest of the screen was working because they could log in, but after a few more pointed questions I've established that it's definitely not talking to the PLC in any way shape or form.

I've got someone to ping both the PLC and the HMI from the office - the PLC responds, and the HMI doesn't. So I'm guessing that either the HMI has lost a communication parameter of some sort due to the low battery, or while messing about with it someone has knocked out a comms cable. We have a guy onsite tomorrow and I'll know more.

Man, I hate coincidences!

Last edited by ASF; July 11th, 2016 at 01:04 AM.
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Old November 30th, 2017, 07:23 PM   #3
uali4572
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Solution

Did you find the solution to your problem?
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Old November 30th, 2017, 09:08 PM   #4
ASF
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Yeah, the HMI was kaput. Had to be replaced. As I said in my second post, it wasn't actually communicating with the PLC at all, or even responding to a ping even when plugged directly into it. Once I realised that, I just ordered a new one and swapped it out
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Old November 30th, 2017, 10:00 PM   #5
uali4572
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Thanks for the quick response. I have two CPU's connected to the panelview, the readings from micrologix 1100 show as Timed Out. It feels like it lost the Micro lost it's IP address.
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Old December 3rd, 2017, 08:28 PM   #6
ASF
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You might be best to start a new thread and describe your problem fully, you'll get more assistance that way.

Give full part numbers for all the equipment, describe what is and is not working, and if possible sketch up a network map.
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