Why does Start Digital Edge in Start Trigger.vi do a kind of timeout?

[laskar01]

Hi I am doing a manual trigger on my hardwareboard by inserting a 5 volt source into the selected triggerchannel a couple of seconds after I push the start button.

The generation never starts. But if I put the trigger signalchannel  equal to the external sampling clock the appended vi work.

Example I use PFI7 as trigger source which is also the source of the sampling clock.

Could somebody explain?

Kindest regards,

Lasse

[laskar01 · Accepted solution]

One cannot just insert a wire with a 5 V potential to PFI6 for instance if PFI6 is used as a trigger for "Start Digital Edge" daqmx -vi. The pin is floating and just inserting 5V does not guarantee a low to high edge.

If I use a potentiometer to pull the channel low first, and then increse the voltage, the trigging happens.