Analog output range on 4461

[NF1]

Hi,

I'm a bit confused on the AO capability of the PCI NI4461 24-Bit, 204.8 kS/s board.  The data sheet says that the output ranges are +/-100mV to 10V.

My Measurement & Automation Explorer's Test Panel settings :

DC Voltage

Max/Min Outputs setting +/-10V

Pseudodifferential (though I see the same thing with Differential)

Update Rate 20000

The output voltage seems linear between +/- 1.0V.  But then after about +/-1.20V, the output voltage doesn't seem to get any larger.  My output voltage seems to be maxing out at +/-1.2V even though my range is +/-10V.  M&A Explorer lets me send 10V, but I don't see a difference in the output.

I'm using a cap probe to measure the response of a part which moves linearly with voltage/current.  I'm also measuring the current output from the 4461 board using a current prober.  I have pretty good confidence that these two sensors are configured correctly as they are used with the 4551 board with no problem.

Help!

Thanks in advance,

Nia

[stilly32]

Hi Nia,

There are a few things I would try:

Do you see this limitation if you just do a loopback (feed the AO to the AI)? This will eliminate the external connections as being a problem.

Also, do you see this behavior on both channels? Its possible that a channel is locked on a fixed gain setting - this is unlikely to happen on both channels though.

Do you see the same behavior if you do a sine wave?

Please try these out - if one channel works and the other doesn't, its probably a HW issue and you'll want to send the board in for repair. Let us know how it goes.

Andrew S

National Instruments