does the dsc tag engine interpolate data points when using deadband constraints?

[dingler44]

I like the whole deadband idea of eliminating data noise to some degree... but as I'm gathering data say from multiple sensors... I'd like to compare the sensor readings in a plot.
Say that I don't want to use the DSC historical trend plotter... I want to be able to archive all my data into a Citadel database and export it to some other type of database. Does DSC interpolate data streams so that there are an equal number of datapoints or would I have to figure this out on my own?

[Greg Caesar]

From within DSC, you can take the output of a "Read Historical Trends.vi" and pass it to a "Decimate Historical Trends.vi". The "Decimate Historical Trends.vi" will give you data with a common timestamp.

As far as exporting the Citadel database to another location, you can do that easily as well. Internally, the Citadel database holds two tables : The "points" table and the "traces" table. Accessing data from the "points" table will give you the real logged values and timestamps. However, the "traces" table interpolates data to common timestamps, and allows you to pull data from multiple tags against the same timestamp. Therefore, the traces table is extremely useful for comparing / correlating / trending data. You can access these two tables from external softw
are such as Excel or Access very easily. For step-by-step procedures, in LabVIEW goto "Help >> Datalogging and Supervisory Control >> Historical Logging and Extraction >> Querying the Citadel Database".


Regards,
Greg Caesar
National Instruments,
Applications Engineer