calibration

[Labmaster James]

What could cause the AI channels on a 6111 to mis-behave? If a 10v sine is applied to AI1 the reading from MAX is just +0.7v to -0.7v. Calibration is out? or something more serious. Max reports no errors with the card. AI 0 reports 0.05+-v. What could be wrong?

[Ben]

Check if outputs/inputs are configed for differetial.

Apply know voltage and then use Max to test. If voltage is right, calibration is right.

Check this and re-post with whatever you find.

Ben

[Labmaster James]

I unplugged all connections; generated a sine wave from the AO using MAX, connected this to the AI +and- and the result was correct. Although, not quite right. I got marginally less volts than expected.
However, using an input of around 1v in a short time scale (10ns) the card only registered 0.2v. This signal is unknown to be ground referenced or floating.

[Filipe A.]

Hello;

The best bet it to double check how the signals are connected on the input channels, and what is the input mode that the DAQ board is configured to work at.
Regards
Filipe A.
Applications Engineer
National Instruments

[Ben]

James,

Please clarify, are you trying to measure a sine wave with a period of 10ns?

Thats 100 Mhz! the board can only sample around 5 MHz if my memory serves me.

[Ben]

If yes, you will have to go to a scope card.

The PCI bus can not keep up with data coming in that fast.

Ben