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Battery voltage 2122 volts DC?


wpns Aug 13, 2010 05:50 PM

I've got a CR10(x) that lost it's mind about a week ago, and is reporting the number 2122 for a bunch of it's readings.

I've read the program from the datalogger, opened the DLD file, confirmed that the first instruction is 10 (battery voltage), and I can read and write that location using PC208W.

I can set the number to zero, but every 10 seconds the datalogger sets it back to 2122.

Any idea what might have happened to it, or what other remote diagnosis I can do to it?

Here's a log of my program output:
FSA...1A
R+2777. F+62230. V5 A1 L+2777. E34 99 64 M0256 B+3.2763 C3141
*
Select...2413J
<
Configure...Got 27 bytes: 00 40 00 01 03 04 0b 13 18 19 1a 1f 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 00
Dump Binary...Got 105 bytes: 4b 0d 0a 02 df 01 79 00 20 4c 84 c0 00 00 00 00 00 c6 d5 d7 24 c0 b1 34 4b c5 d7 ca 3a 00 00 00 00 46 84 1e 56 c6 ce 07 bb 00 00 00 00 42 c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 4c 84 c0 00 4c 84 c0 00 4c 84 c0 00 4c 84 c0 00 4c 84 c0 00 4c 84 b0 00 4c 84 b0 00 4c 84 b0 00 4c 84 b0 00 4c 84 b0 00 7f 00 f8 2f
-------------------------
End...E

Minutes Since Midnight: 735
Time 12:15
Vcc: 2124.0
Head_in_B: 0.0
CisternCB: -53.5
Head_in_A: -0.7
SolarTank: -27.0
Enc_RH: 0.0
ITemp_C: 33.0
Freezer_C: -51.5
KWHRMETER : 0.0
HPglobal : 3
HMglobal : 0
BPglobal : 0
BMglobal : 0
HPlasthr : 2124
HMlasthr : 2124
BPlasthr : 2124
BMlasthr : 2124
KWHRlasthr : 2.1
HPlastday : 2123
HMlastday : 2123
BPlastday : 2123
BMlastday : 2123
KWHRlastday: 2.1
-------------------------
Current Cistern Gallons: 0


So it's really sending those numbers, it's just that they don't make any sense...

Thanks in advance for any hints as to what I might do remotely, I'm not scheduled for a site visit till late October...


IslandMan Aug 13, 2010 06:35 PM

Whenever I see the battery voltage doing strange things the 1st thing I look at is the analog voltage inputs on all the channels. Most of the time, it's been an over-range condition on a channel screwing up the input multiplexer.
This is also a clue in the status line:
E34 99 64
34 being the number of E08'S
99 being the number of overrun errors
64 being the number of times the program stopped due to low voltage.
8888A clears them all
Ref, CR10X manual, Page 5-3


Dana Aug 13, 2010 08:04 PM

64 being the number of times the program stopped due to low voltage.

The datalogger will stop executing its program if the battery voltage drops below 9.6V. This is because good measurements cannot be guaranteed when the voltage drops that low (including a battery voltage measurement). This would certainly indicate the power supply needs to be checked out. Also make sure you don't have some sort of grounding issue (transient voltages or a ground loop) -- that is one cause for watch dog errors (E08 errors).

Note that all error counters on the CR10X max out at 99. Once you clear the errors and correct what you think is the problem, make sure to monitor these values. If they continue to increment, you'll need to dig deeper into the problem. These kinds of statistics can be monitored in LoggerNet's Status Monitor (right-click a device to change what columns are displayed for it), or by opening the Station Status window from the Connect screen.

Regards,

Dana W.


wpns Aug 14, 2010 09:30 PM

Thanks for the feedback guys!

I've looked thru the logs, and those error numbers were there since at least late 2008. I reset them this morning with 8888A, and they have not increased since then, though I'll probably add some code to watch for them to be non-zero.

E08 is watchdog timer, yes?

I'll have to have someone take a DVM to the power supply and see how it's doing, I can't imagine anything else is overloading the inputs, as they are all either powered from the CR10(x) or switch closures.

Thanks!


wpns Aug 14, 2010 09:35 PM

While I'm doing some more defensive programming, I thought I should watch the lithium battery voltage value returned. What's a reasonable range of values for this battery?

Thanks!


kirving Aug 14, 2010 09:44 PM

We've seen similar screwy values in some remote sites, and have never really found an explanation for some cases. I suspect that static build-up might be a factor, along with poor grounds, but other things like radios for telemetry and electric fences might also be suspects. It's not easy doing systematic troubleshooting for intermittent or rare problems on sites we can only visit a few times during the year by helicopter.

I look forward to hearing more about your problems and any solutions!

Ken


wpns Aug 14, 2010 09:47 PM

Speaking of defensive programming, I thought I'd confirm the signature value, but the description is a trifle confusing.

Page C-5, section C.3 Generation Of Signature

says T2 = shift left(S0(n)) + carry

That's the same as an 8-bit rotate left operation, yes?

Thanks!


wpns Aug 15, 2010 06:51 PM

What measures the lithium battery voltage? Mine's been _CLIMBING_ over the last few years.

The end of 2008 it was 3.1387 volts
Now it's 3.2750 volts. Looking at the logs in between it's been gradually rising, does that make any sense?


IslandMan Aug 16, 2010 10:33 AM

The CR2530 is a 3.0 Volt, 270 mAhr battery. The CR10X manual suggests replacement if the battery voltage drops below 2.4 Vdc. In an office environment, the battery life is ~ 4 years, longer if the CR10X is continually powered. The battery can actually die and as long as you have 12 Vdc power, the logger will function correctly. If you remove power with a dead lithium cell, the logger will reset the clock and lose the stored data. I'm not sure how the battery is measured, someone at CSI will have to answer that one.


aps Aug 16, 2010 12:02 PM

There is no reason the lithium battery voltage should climb other than temperature - the voltage is quite temperature dependent, i.e. the higher the temperature the higher the voltage.

The voltage is measured as another analogue input, albeit by a resistive divider which is switched in during the measurement.

As a very crude measure when the voltage gets down to 2.75 V or there about at 23 C then you only have about 15% capacity remaining. Remember though this battery is not used if the logger has 12 V supply permanently connected. It will only drain due to ageing and being loaded for occasional measurements of its voltage.

One other point re the error counters. In the CR10X if all the error counters are showing large numbers, it is possible this has been caused by one serious crash of the logger. In some instances if the logger crashes it can corrupt those memory locations during the crash and for obvious reasons cannot reset them when it recovers. So you can jump from a clean slate of errors to what appears a dire situation caused by one watchdog reset. In that case the overrun and low battery counts can be spurious. Reset the errors and monitor further (as you have done).

I would advise getting your person on-site with the DVM to measure the voltage on each analogue input relative to ground to check for high voltage which could be caused by some insulation breakdown. Also check for condensation on or around the wiring panel. (12V on the wiring panel leaking into an analogue input could cause this.)


wpns Aug 16, 2010 08:59 PM

I knew the lithium battery was not used when the logger was powered, and it's been powered since it was installed around the end of 2008, but checking the logs I can see that the voltage has been steadily rising over time.

Or, the measurement has been rising over time, which means something's drifting. I wasn't sure if that was significant or not, if the same ADC that's going nuts on the other readings is used for the lithium battery, or if there was anything else I could tell from that anomaly.

Hmm, that's weird, the logs for my other CR10(x) show that it's voltage has been steadily rising over the last couple of years as well. Not a lot, 3.1514 -> 3.2424 volts.

I'm not sure that having someone poke around on the wiring panel with a DVM would be a good thing, I'll probably stop at confirming the supply voltage is sane... Way more stuff can go wrong if they open the box!

Thanks for the feedback!


aps Aug 17, 2010 11:40 AM

Looking at datasheets for different makes of that battery there is no evidence of the battery voltage increasing with discharge when loaded with constant load resistor. I did find one data sheet that showed the voltage increased a little initially over time when it was subjected to a pulsed load. The logger is effectively applying a pulsed load when it does the measurement (only a 50k load though) so this might be an explanation.

Thinking about this further if the lithium battery (which is only measured once a day) is still reading OK but the main battery reading is bad this would seem to indicate a memory or OS corruption issue, as the two battery voltages are measured on the same input of one of the internal multiplexers (there is one extra multiplexer used to switch between the two).

If you are able I would try at least either remotely resetting the logger and/or loading the program again, if this is possible. That might solve a memory corruption problem but not an OS corruption.

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