AI scaling range

[HeikoM]

Hello,

I have a issue with the AI scaling with a NI6229 Device.

Set the Input to 0.0V, then is the return value of aiPolynomialScaler(..) -10.63V and if the input 10V, i get -0.63V.

And this will continue linearly:

Input         Output

-10.0V ->  0.63V

  -5.0V ->  5.63V

   0.0V ->  10.63V

   5.0V ->  -5.63V

 10.0V -> -0.63V

Is there a adjustment for a accurate conversion or I have to do my own conversion scaling?

The Parameter "gain" for aiConfiguration(..) is 0 (input range from -10V to 10V).

The Inputsource is a AO-Channel.

 Kind regards,

Heiko Mayer

[JoeFriedchicken · Accepted solution]

Hi Heiko,

I overlooked the changes you made to the example to get the 622x devices to work, and there's a mistake in your configuration: M Series boards (all 622x, all 625x, all 628x) do not support unipolar AI ranges [1]. In your call to aiConfigureChannel(), you need to use tMSeries::tAI_Config_FIFO_Data::kAI_Config_PolarityBipolar. Another thread in this sub-forum also points this out [2].

[1] M Series Manual, section 4-3, page 49
https://www.ni.com/docs/en-US/bundle/pci-pcie-pxi-pxie-usb-62xx-features/resource/m-series-user-manu...

[2] register guide for 6220, 6224
https://forums.ni.com/t5/Driver-Development-Kit-DDK/register-guide-for-6220-6224/m-p/758884?query.id...

[HeikoM]

Hello Joe F.,

that´s it!

Thanks a lot!

Kind regards,

Heiko