problems reading cmos levels?

[henry99]

I'm using a PCI-6221 card on a digital input.  I hooked up a CMOS line to it and the following happens:

1) If I measure the voltage with a voltmeter, it says 3.3V

2) As soon as I connect the wire to the daq card port 0 line 0, it goes from 3.3V to 1.6V

3) When I run my program, it always says FALSE on the DIO line

4) If I connect a jumper between port 0 line 0 to +5V, it says TRUE

Is there any way I can get the cmos logic to work here without adding too much componentry (or using a different port)?  I'm guessing the weak pull down is dividing my voltage in half and it's not working.  Can I disable the internal pull down somehow?  Interestingly, I hooked up a quadrature counter to CTR0 on lines PFI8 and PFI10 and it seems to work fine without problems with the same logic!

I also have a PCI-6202 that I haven't hooked up yet.  Would this be any different?

Thanks for any help.

[henry99]

Also I'm using a SCB-6868 if that makes any difference.

[henry99]

I tried it with my Labjack and it works fine at 3.3V.  Any ideas what I can do to get Labview and my pci 6221 reading these 3.3V levels without dropping them 1.6V?

[altenbach]

These three posts have been combined into a new thread, so let's continue over there for simplicity.