Problem in reading history data from Citadel

[Ravinder Jagdev]

While Iam trying to fetch some (max of 1 hour) data from the citadel database Iam getting some error. I have attached a bmp file which is a screen print of two errors. What is this error ? How can I rectify it ?
I have re-installed the whole OS & LabVIEW but the scf file is the same, still the problem persists. Is there some problem in the scf file.

[Carl L]

Ravinder,
Can you describe a little bit further what you are doing when you get the crash? There are many ways to get data from Citadel. You can get data by doing querries with VIs in LabVIEW DSC, you can view trends in MAX, you can export data to csv files in MAX, you can querry with SQL through ODBC.
What version of LabVIEW DSC and Citadel do you have? Is it just one database that causes problems or is it all Citadel databases?
Carl L
National Instruments

[Ravinder Jagdev]

Thank you Mr. Carl for your prompt reply.

I want to describe the manner in which my application is storing the data.

1. I have two folders, one folder contians the current data and the other folder contains the back up data.

2. Program takes back up every one hour from the current data folder to the backup folder in the the folder of todays date (d:\Back_UP\2004_03_12)

3. On the next day my application creates another folder (d:\Back_UP\2004_03_13) and the data is now backed up in this folder.

4. The data in the current days folder (i.e., d:\Back_UP\2004_03_13) is accessable through the VIs in LabVIEW DSC but the problem is in the data which is in the "older folders" (d:\Back_UP\2004_03_11, d:\Back_UP\2004_03_12).

Note : This app
lication was running fine on the same PC but I don't know if anyone has done some changes in the configurations or tag file. Right now Iam facing a problem.

Iam listing my observations in detail for the data in the "older folders"-

1. I have not tried to fetch the data with SQL through ODBC.

2. If I give a query for fetching the data from the Citadel using the VIs in LabVIEW DSC I get the errors which are there in the bmp files.

3. The data is accessable through MAX and I can even export it.

4. Once the data folder is listed under the "Historical Data" and the MAX is closed Iam able to fetch the data from the Citadel through the VIs in LabVIEW DSC.

I have LabVIEW DSC 6.1.

Thank you.

Ravinder

[Carl L]

Ravinder,
If it was working before the easiest would be to find out what changed. None of what you have described so far points me to anything specific to look at. There is nothing in the SCF file that I can think of that would affect this.

What method are you using to archive the data? Are you copying the data from one folder to another, or are you using the historical data VIs in LabVIEW to archive the data? If you are copying the data then that could be the problem. You should be using the LabVIEW VIs to archive (copy) the data.

Once you view the data in MAX, you said you were able to also querry it from LabVIEW afterwards. If you then do another archive to the same folder, are you able to querry from DSC with out first going into MA
X? You said you archive once an hour and switch folders once a day, so I assume that you do multiple archives to the same folder.

Until we know exactly what is wrong, I can't say if upgrading to LabVIEW 7.0 would help. However in general upgrading would be a good idea. Specifically we updated the database structure of Citadel to be more robust. See www.ni.com/upgrade for more information. Short of upgrading I would recommend to make sure that you are using the latest version of Logos (the Citadel driver). http://digital.ni.com/softlib.nsf/954feaeea92d90918625674b00658b83/c1a484551a75614686256ae300734336?OpenDocument

Carl L
National Instruments
www.ni.com/ask

[Ravinder Jagdev]

Dear Mr. Carl,

1. Iam using the historical data VIs in LabVIEW to archive the data.
2. Does multiple archives to the same folder cause any problem ? Same program is tested on another PC ... it is working fine.
3. "If you then do another archive to the same folder, are you able to querry from DSC with out first going into MAX?" - I shall perform the experiment and confirm it.

regards,
Ravinder