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Historian Web Service no longer returning good data

May 20, 2013 at 8:27 PM
I am no longer getting good data from the Historian Web Service (Statistics) at:
every value is Quality: Unknown ReceivedTime: 1/1/1995 12:00:00 AM value: 0.0

I am running openPDC 1.5.226.
May 20, 2013 at 8:41 PM
Edited May 20, 2013 at 8:54 PM
Here's a few things you can try:

(1) Check disk space on where historian data files are located (by default, ...\Program Files\openPDC\Archive) - a full disk can cause this error
(2) Stop the openPDC service then delete *_dbase.dat, *_startup.dat and scratch.dat (i.e., anything but a ".D" file) in the archive folder restart PDC and see if the historian service returns to normal operation? This deletes the non-data related files that may become corrupted due to an improper shutdown or other activity - these will be recreated once the PDC restarts - then you can try the tool again.
(3) If these steps do not work, one of your recent ".D" files may be corrupted (e.g., ppa_archive.d) and may need to be deleted - back up all files before deletion of ANY .D files so you do not lose an historical data.
(4) Also be sure to validate the timestamp of the incoming measurement data and make sure it is good quality and a reasonable time.
May 20, 2013 at 9:19 PM
This is a test openPDC, so I stopped it, and deleted all Archive and Statistics files. Upon restart these files were recreated. The historian statistics metadata look correct, as far as I can tell from a brief inspection. The metadata show the system and concentrator statistics from id=1 to 35, and then a gap until id=957 for the first non-concentrator statistics.

When I use the Historian View, the statistics look good. However, when I use the web service, the data remains as before (Unknown, very old, 0.0). This is true when I use the web service manually from a browser.

I normally use the web service via a program, and didn't notice when the data went bad. It certainly worked fine at some unknown time. Non statistics data still arrives in good form.
May 22, 2013 at 8:06 PM
Very sorry, yet another bug in my code...