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PicoLog with unexpexted power loss

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PicoLog with unexpexted power loss

Postby majs » Tue Apr 12, 2011 10:55 am


I'm trying to collect data from an ADC-20 logger with PicoLog in Windows 7.

My problem is that the process must be completely automated. I have already been able to make PicoLog start recording as soon as Windows starts, but when where is a power loss, Windows will shut down unexpectedly and the file that PicoLog was currently saving data to will be corrupted.

I have considered installing a battery in my computer so Windows can shut down properly when there is no power, but when the computer starts again after such a shut down PicoLog cannot connect to the data logger. I get the following error as a popup window when PicoLog starts (translated from swedish, sorry about that): "Unit with series 'AS296/104' is missing and no ADC-20 reserv unit is connected". Since the process must be automated there is no person there to click ok and remove and plug in the logger again.

Any ideas on how to solve either the problem with connection or if there is another way to make this work.

The information before the power loss is the most needed one.


Re: PicoLog with unexpexted power loss

Postby majs » Tue Apr 12, 2011 11:56 am

Acctually, I found this article now:
And these are the basic steps I've been following for the restart, but I cannot agree with:

The program will restart, creating a new data file with a serial number attached, such as ‘oven1.plw’. The data from before the power failure will be safely stored in the original ‘oven.plw’ file.

Since in my case "oven.plw" cannot be read in PLW-Player.


Re: PicoLog with unexpexted power loss

Postby FrancisL » Tue Apr 12, 2011 6:03 pm

Just a brief comment. I have had Picolog running (I have DrDaq) for some years and there have been several times the power has gone down or Windows has crashed, but I have rarely lost the PLW File. It has been generally ok up to a few minutes before the power down. This may be because Picolog is only logging every 30s, and even then it only actually writes the PLW file every 5 mins.
So most likely it will not have the file in a writing state when the crash happens. However it is still possible and probably more likely the greater the sample rate.
A possible way might be to have a process running that copies the current PLW file every few minutes to somewhere so you can use that one if the main one does get corrupted
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Re: PicoLog with unexpexted power loss

Postby majs » Thu Apr 14, 2011 6:54 am

I'm logging a few times per second so it makes a lot of sense that when power failure occurs, PicoLog tries to write something. I will also consider your idea of making backups of the files every few minutes, but since the files are so large this might not be a solution.

Since I can accept that the last minutes (maybe 2) of data will be lost, I considered setting up PicoLog so that it creates a new file every two minutes, but then if would be so hard so overlook and analyze the data afterwards! Can I append several PLW-files in some way?

Edit: The copying idea seems really interesting to me now, but when I try to copy a file that PicoLog is currently writing to as suggested, then the copy will most likely be broken. Any ideas?

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