Signal Compression with Write LVM

[MPlattner]

I am reading data from a PCI-6220 DAQ card (4 channels).  When I use the Write LVM VI, the data is recorded with an X-Value staring at 0 incrementing at the expected sample rate.  The Time-Pref is Relative. A single header was configured and it displays the correct date, time, channels, etc. 

However, when I pass the same data through the Signal Compression VI with a reduction of 10 and the mean selected and plotted, a number of differences are seen.  The header is missing and the X_Values start at 3.20E+09.  The Time_Pref is Absolute with a date of 12/31/1903 and time of 17:00:00.  Also, if I stop acquiring data the raw data shows the correct time gaps in the data (plotting on a chart) once I resume.  However, the Signal Compressed data erases old data and restarts.  When I use a probe to look at the data going in and out of the Signal Compression VI, it looks the same.

Any ideas?

Thanks, Mike

[MPlattner]

I used the incorrect term.  It is Sample Compression.

[ChrisJ]

Hi Mike,

Is this reproducible? Do you see the same behavior if you create a simple program using Simulate Signal VIs to generate your signals ?

Thanks,

Chris J