Using multiple channels with DAQmx reference trigger (analogue edge)

[Schwuck]

Hi Chris,

Running the original code with 4 channels wired the 'task/channels in' (my global virtual channels named - AnIn 1:4) with AnIn 1 named as the 'source' results in the following error:

Code: -200264

with the text:

DAQmx Start Task.vi:71<append>

<B>Property: </B>Ref.AnlgEdge.Src

<B>Corresponding Value: </B>AnIn 1

<B>Number of Channels in Task: </B>4

<B>Task Name: </B>AnIn 1:4

[Chris_Garratt_NIUK]

I believe this should help. If you wire your trigger signals to APFI lines and use those as your reference triggers you should be able to acheive the behaviour you're looking for.

Why do I get Error -200264 When Performing Analogue Reference Triggering?:

http://digital.ni.com/public.nsf/allkb/1CD33848C0CB0FC98625711400630A9D?OpenDocument

Best Regards,

Chris

[Schwuck]

I read that file that you provided a link to. It's unfortunate that I can't set the number of pre-trigger samples to 0 (I have to set it to a value not less than 2) and simply record post-trigger samples at the rate I want. That would allow me to wait for a trigger on any one of the analogue input lines prior to recording and data and avoid the cause of the error.

I only have APFI0 available on my 6251. I'll have to think of a way that I can wire and select from 2 separate differential voltage inputs on that single line as the sorce of my trigger.

[Chris_Garratt_NIUK]

From the look of things, it will may not be possible to implement a hardware solution with the kit you've got. You will either need different or additional hardware such as some sort of switching circuit for the APFI line.

Regards,

Chris