DAQmx Create Scale doesn't work

[Fulvio]

Thank Kevin.

Unfortunately it is not a signal variation problem. The same problem constantly occurs whether I create the scale by creating with the Linear or Map Ranges scale.
For this reason I am very very confused.

I try with a battery and I'll let you know.

Thanks again

Fulvio

[Fulvio]

Good morning Kevin,

I would like to update you.

Last night I was thinking that I could connect the same signal to the first three channels. So I did it and the problem is still there.
Do you have any advices?

Thanks again.

Fulvio

 

  

[Kevin_Price]

That was a useful test, and now that you showed your *code*, I can see that you're having the same problem as the OP for this thread.  And the solution is the same as the one given by crossrulz back in msg #5 and PsyenceFact in msg #6.

The values you put into Max and Min inputs when calling DAQmx Create Virtual Channel need to represent the *post-scaled* Max and Min values.

So when the raw voltage range is +/- 5V, then:

- when scaling by 100x, wired Max and Min values should be +/- 500.

When you specify the *post-scaled* Max and Min as +/-5, DAQmx is figuring out what raw voltage range to use.  But the device doesn't support a +/- 0.05 range, so it uses the next bigger range it actually supports.

-Kevin P

[Fulvio]

Thanks again for your answer and for the explanation.

Now it is clear to me how it works.

I simply upload the correct code for the benefit of other users.