NI PXI 6251 Analog Trigger (APFI0) Calibration

[drian]

Hello! Is there a way to calibrate analog trigger, APFI0, and correlate to analog input channels? I'm using NI PXI 6251 for closed-loop bang-bang control and since the loop rate must be high as possible, I used analog trigger to control the output by using Analog Comparison Event. To read the feedback, I also connected Analog Input AI1 to APFI0. What I noticed is the difference in reading in AI1 to the set voltage trigger to APFI0 when the target is achieved (Analog Comparison Event status is toggling). This means APFI0 and AI1 has different readings. Is NI providing a way to calibrate?

[Paul-B]

Hello Drian,

Just to make sure I understand your question, are you trying to calibrate an analog input channel?

If you have created a task such as acquiring a voltage analog input for your PXI 6251 using Measurement & Automation Explorer (MAX) it is possible to configure many different settings. Under the configuration tab of your task there is a setup section where you can change different settings and access a calibration wizard. Selecting the calibrate button under the calibration tab will direct you to this wizard.

How have you configured your setup, are you using LabVIEW or some other method of programming?

[drian]

Hello Paul,

I wanted to calibrate APFI0. What happens in my application is that when I set analog trigger to 2V example, it will actually trigger about 50mV lower. Offset will depend on specific the voltage level. The analog channels are pretty accurate though. I'm using Labview in my application.

Thanks!

[Paul-B]

Hello Drian,

Here is a useful link to a calibration procedure manual which includes PXI 6251.

CALIBRATION PROCEDURE:

http://www.ni.com/pdf/manuals/370937k.pdf