Trigger Solenoid Valve (Digital Output)

[M^2]

I was wondering wether it is possible to use a trigger to send a signal to a digital output. I currently have to send a signal to a solenoid valve when the slope of the data I am acquiring starts to become negative. I know LabVIEW can do triggered data acquisition but can it send a signal to a digital output based on a trigger (falling edge)? I already know what code the signal should send. However, i tried trigger.vi without success. I am relatively new to LabVIEW and would really appreciate any help.

[Paul_C.]

Hi M^2,

If all your trying to do is a software timed trigger as shown in the vi that you provided, theres a few things that I would change.  First off, I would create the digital output channel and start it prior to the loop.  Second, I would initialize the value of the digital output to high (I was using an inverse logic LED output) prior to the loop.  Then after the trigger is found, write the digital output to the opposite (low).  In addition, I changed the DAQmx read to 1 channel with N samples (1D DBL).  This seemed more appropriate if you’re just using one analog input channel. 

I've gone ahead and uploaded the code I modified.  This is setup to my parameters.  Basically, I triggered when my thermocouple voltage rising edge went over 0.29V.  You will need to change these settings back to what you need for your application.  Also, I wanted to note that once the digital output is changed low when the trigger is found it will remain low until changed high again.

I hope this helps,
Paul C.

Message Edited by Paul C. on 08-16-2007 03:34 PM

[M^2]

I cannot seem to open this file. I have LabVIEW 8.2.1 and this was done in LabVIEW 8.5. Is there any way to view this file?

[Paul_C.]

Hi M^2,

Here is the labVIEW 8.2.1 version.

Paul C

Message Edited by Paul C. on 08-16-2007 06:39 PM