Re: strange output range of pci-6071e board

From: Jason Z.S. Guo <JasonGuo_at_pcg.wustl.edu> · Date: Tue, 05 Nov 2002 14:21:09 -0600

I just realize that (from 6071E datasheet) when output range index=2 and 3,
the ranges are +/-EXTREF and [0, EXTREF] instead of fixed +/-1 and [0,1].
That solves the problem.

Jason

"Jason Z.S. Guo" wrote:

> I am using National Instruments pci-6071e board on Redhat 7.1. The comedi
> version is comedi-0.7.65/comedilib-0.7.19.  We meet a problem that when
> output range index is 2, the output range is not [-1, 1] claimed by
> demo/info and comedi_get_range(). We used demo/outp and a multimeter to
> measure the outputs, which are 58mV when sample=0, 33.2mv when sample=2048,
> and 8.3mV when sample=4095. But when output range index=0, the range is
> correct (comedi_get_range() says the ranges is [-10V, 10V]. Our measurement
> is: -9.96V when sample=0, 33.2mV when sample=2048, and 10.02V when
> sample=4095.) When output range index is 1 ([0, 10]), the range is also
> correct, but when index is 3 ([0,1]), the range is wrong again. We tested 2
> boards, both of them have this problem.  Any idea? Thanks for help.
>
> Jason
>
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