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Unable to read voltage in excess of 5v in vb6 with DAQ6036E


I have a problem reading in analogue voltages with my DAQ6036E
When I use the Measurement and Automation Software I can read a voltage of say 7.5v without problem.

however if applying a signal of 7.5v to my VB6 software:-
AI_Read returns 32,767 and
AI_VRead returns 4.99v

voltages below 5v appear to measure correctly.

Literature indicates that being 16-bit bipolar the card should return -32,768 to +32,767 (16-bit devices, bipolar mode).
so 7.5v should be around 24500.
It would seem that the card is returning values on the scale 0 to 65,535 for 0 to 10v (16-bit devices, unipolar mode),
but the software wont accept values in excess of 32767, so anything in excess of 5v gives a result of 5v, but this is
only a theory.


I am using referenced single ended inputs and have used AI_configure to set this.

status = AI_Configure (deviceNumber, chan, inputMode, inputRange, polarity, driveAIS)

I have tried individual values for chan and also -1 to set all channels.

I have tried input modes  of :-

0: Differential (DIFF) configuration (default).
1: Referenced Single-Ended (RSE) configuration.  (The one I would expect to use and which works with the Measurement and Automation Software)
 and
2: Nonreferenced Single-Ended (NRSE)

I have tried various input ranges - 20 being the value I would expect to use (-10v to +10v)

I have tried polarity 0 (bipolar) (The one I would expect to use) and 1 uniploar

and also 1 and 0 for driveAIS

I dunno what else to do. Help!

Alex
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A bit more searching around and I discovered that I must set gain to 0.5 (using value -1) for -10 to +10v range.
Problem solved!

Alex
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