Signal amplitude error using Labview acquisition

[silverfox]

Hello,
I currently use the RP team Vis (thanks to you!) for signal acquisition, amplitude and duty cycle analysis with Labview. The app works fine, but I get about 20% error on the restitued amplitude signal.
For example, I first calibrate the signal amplitude using RP device and Cal Scope application with web browser to: square wave signal, 0 - 5V amplitude. Second, I launch signal visualisation with my Labview acquisition (based on provided examples), the signal amplitude becomes 0.2 - 4.4V.
Does someone understand?
Thank you for helping.
Guy

Labview 2012sp1
RP ecosystem 0.93-14