HTV locks up

[David Moerman]

I am running DSC v6.1 with the patch installed from Jan 15/03. (ftp://ftp.ni.com/support/labview/labviewdsc/fixes/6.1). I am logging about 160 tags at 1 sec intervals (approx). I am calling the classic HTV programmatically using the "Call HTV.vi", which seems to work well. However, after the 1st call, the user shuts down the HTV (fine), but after the 2nd call the HTV stops responding to the user. In the upper right corner it has 2 animated rotating arrows, along with a message of "Accessing Data" (something like that). After this, every method I attempt to restart the HTV, short of shutting down LabVIEW, results in the same HTV screen coming up. This of course means that the HTV is not shutting down, so I attempt to force a shutdown with VI Server-->Abo
rt VI, which seems to work OK (no error returned). However, after I do this I cannot programmatically restart it with "Call HTV.vi", as it claims that the trender is "already running". I CAN restart it with the Run VI method, but I can't specify trends that way, so that is no good. I am stuck.

[vg]

Hello.

Most of the time, problems displaying historical database is related to a corrupt database.
If this is the case, try to access the database from the Historical Trend Viewer (in MAX) to see if this gives you any problems.
If this works fine, there might be a problem with the installation of LabVIEW DSC. Try repairing the DSC installation, and as last resource try reinstalling DSC.
Now, if MAX does not let you access the database or gives you problems accessing the database, try logging the data in a different directory to see if the problem goes away...this will create a fresh new database. WARNING: THE OLD DATABASE WILL STILL BE ON THE OLD DIRECTORY.

If you happen to have a corrupt database, go to the www.ni.com/support/ web page and look for a knowledgebas
e that explains how to fix a corrupt database.
The URL to this document is:

http://digital.ni.com/public.nsf/websearch/6fc62f75b74d706d8625694900768f69?OpenDocument

I hope that this information helps

VG

[David Moerman]

This does not appear to be a corrupt database problem. With a copy of the database offline, I can load traces manually without problems in both the MAX trender and the classic HTV. I will try to load traces with MAX at the same time that the HTV is having problems, when it's on-line, and inform of the results.

Also, I will attempt to re-install LabVIEW DSC, but I don't see how this would help, since I just did a clean install (with the patch of Jan 15/03) prior to running my application.

[David Moerman]

I haven't been able to duplicate the problem as of late. Even so, for my client I put a work-around in my GUI that they can use if it happens again. It uses VI server to abort the HTV and then immediately starts it again using the RunVI method. This seems to work OK, and I haven't heard any further complaints from my client. If it becomes a problem again, I will let you know.