Digital start trigger for a digital input task

[MJHanagan]

Hi all - I have a cDAQ 9172 chassis with two 9401 modules - one in slot 1 and the other in slot 5.  I want to start a digital input measurement task (line 0 on the 9401 in slot 1) using a trigger start (line 0 on the 9401 in slot 5).  Attached is the VI.  I am getting the following error code: -200452 which reads:

Property Node DAQmx Trigger (arg 1) in DAQmx Start Trigger (Digital Edge).vi:1->Flame Out Response Time V1.vi <append>
<B>Property: </B>Start.TrigType

<B>Task Name: </B>_unnamedTask<5>

Can someone explain what I am doing wrong here?

[JÞB]

---

MJHanagan wrote: 

Can someone explain what I am doing wrong here?

---

Yes, At least I think so.

"Pulse Width Signal" has no (default) "value."  Therefore it takes the default value of the type DAQmx Task.  A null Task.  Essentially you ask "Nothing" to do "Something" for your vi. 

You need to create the Task "Pulse Width Signal" somewhere and refer to that Task in your vi. 

[MJHanagan]

Hmmmm, I am a bit confused here.  I thought the Pulse Width measurement was only applicable to measuring the time between signal changes on a single input.  I want to measure the time between transitions of two different signals, specifical the time when one line goes from hight to low and another line goes from high to low.  This is why I separated them onto the two different input modules.  The one module (slot 5) used as the trigger start of the measurment of the second signal (slot 1).

For the time being I took the TTL signal from the 9401 in slot 1 and put into an AI module (slot 6) and successfully triggered the AI task and got the needed result.  I am still curious as to why I can't do the same thing with a DI measurement task.