Analog start trigger for x series card gives an error?

[jcannon]

Hi everyone,

I am having some trouble setting up an analog start trigger for DAQ using an x series PCIe card (6351)... Attached is my configuration... After reading the manual (http://digital.ni.com/manuals.nsf/websearch/08B4B2E1B5373B94862579BA006E6BAB), my understanding is that AFPI0 is a compatable analog trigger for the device; however, the vi will not run and I get an error... Although if I change the soruce to "Force" (which is ai0) it works..

Also, the device document says (pg 11-8):

"To improve trigger accuracy, do the following:

• Use an AI channel (with a small input range) instead of APFI <0,1> as your trigger source. The DAQ device does not amplify the APFI <0, 1> signals. When using an AI channel, the NI-PGIA amplifies the AI channel signal before driving the analog trigger circuitry. If you configure the AI channel to have a small input range,"

To me, this implies that I probably should use "Force" as the trigger soruce anyway (note that the instrunment is used to acquire data load cell data generated from human muscle contractions; so slew rates are relatively low compared to signals acquired from industrial tests).

Could someone please comment on these issues for me?

Regards,

Jack

LV2010

[jcannon]

Ok... I think I have answered by own question... APFI0 needs a low impedence signal to drive the terminal... I mistakenly thought this was an internal terminal or trigger...

So I should stick with using the first analog signal acquired in my DAQ device (e.g. ai0) as the trigger source?

Regards,

Jack

LV2010

[jcannon]

Sorry.... Could some please confirm/comment on my logic above?

Many thanks,

Jack

[Esteban.R]

Hi jcannon

When you run the code without using the the source to "Force" which error gives you?

Regards