How do I set the trace interval for DSC Read Trace.vi ?

[xlAutomation]

Hello;

I am using the DSC Module's "Read Traces.vi" to read historical traces and display them on an xy graph. Normally, I update in real time every second or two and have a time interval of one hour or less, but sometimes, I want to look at a day or more of data on the trend. Since all of my variables are logged in one second intervals (although I do have a log deadband for most variables), this could potentially be a tremendously large array, and I want to minimize CPU usage and eliminate "out of memory" problems.

Does updating the "interpolation interval" value in the vi options cluster update the data point to data point interval for all data points in a trace or just in areas that need to be interpolated, e.g  where there are gaps (due to for instance a data point value not changing more than its log deadband for a period of time)? I am wondering if I set this value to a larger number of seconds, then will it solve my problem or provide no change if all of my data points change continually.

Thanks in advance for the help.

Michael Hampson

XL Automation, Inc.

[SamboNI]

Hi Michael,

I spent a good deal of time playing around with this, and it appears that the functionality of the Read Traces.vi's option input is to interpolate (draw a straight horizontal line in a graph) the data for all traces. This includes those that have updated within the interval (the updates are lost)... and having a larger interval would have more data loss.

If you want to minimize disk usage, you'd want to increase the deadband so that fewer points are written to Citadel - I'm not sure what aspect of your program is concerning you with CPU usage. You mention that all of your variables are logged in one second intervals.

Hopefully I have understood your concern and the workings of this VI. If I haven't, please post some screenshots or describe a little more clearly what you are looking to accomplish.

For future reference, the LabVIEW DSC forum would probably be a better place to post questions, rather than fieldpoint 🙂

Best regards,