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?
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?