Why doesn't transient recording return gnd level?

Instruments PC Oscilloscopes and Recorders
1

I’d like to use transient recording with my PCSGU250. Why doesn’t the saved data file include a gnd level? Without it, I can’t get absolute values.

2

Thank you for your comment.

The reason to this is that during a long recording period the user may change the GND level.
In this case the GND level indication at the beginning of the record is incorrect.

As a workaround you can disconnect the signal (or use coupling GND ) and do a second short recording and save it to file. This file shows the GND level.