strange output range of pci-6071e board

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

Received on 2002-11-05Z17:59:59