I'm trying to perform table calibration of multiple analog channels coming from SCC modules (ANALOG1_AIN1 physical channel is SCCMod0_ai0, etc...). When I turn off calibration and apply reference voltages at the min/max I get the following:
Ref, DAQmx value
-10, -10.1
0, -0.05
10, 9.98
When I apply those to the scaled and un-scaled inputs of the calibration (AI.ChanCal property node) I get the following error:
DAQmx Save Global Channel.vi:5070001<append>
<B>Property: </B>AI.Min
<B>Requested Value: </B>-10.0
<B>Maximum Value: </B> 10.0
<B>Minimum Value: </B>-9.900990
<B>Channel Name: </B>ANALOG1_AIN1
<B>Task Name: </B>ANALOG1_AIN1
Using the wizard produces a similar error.
Why is the Ain Min/max being enforced for the un-calibrated actual response? It is what it is right? I'm not exceeding the actual min/max (Using a calibrated HP5700A). Calibration requires me to use a reference at the min and max yet DAQmx won't let me use those (Table mode) because the actual un-calibrated values don't fall within those limits.
The bug here appears to be that the AI.min and AI.max values are being 'processed' through the calibration in a race condition like fashion.
What's the work around? Polynomial based cal? Fudging the endpoints (With resulting loss of accuracy)? Or is there some trick here that I'm not seeing (Like temporarily disabling the min/max test if that's even possible)?
Thanks,
XL600