Question On Sequencing

[User123]

Hi

 

I am a beginner, and my question might have a very simple answer. 

 

I am trying to set up a sequence such that a part of an instrument (controlled by LabJack U12) would turn on, and then after a set period (e.g. 30 minutes), turn off, and then repeat this for a prespecified interval of time (e.g. 48 hours). In short, over a 48 hour interval, I want the instrument to turn on after every 30 minutes, stay on for 2-3 minutes, and then turn off again. 

 

Is it possible to do with DAQfactory? 

 

How do I begin? Should I just use the while (1)> set> delay> endwhile steps? 

 

Thanks!

[AzeoTech]

Sure, just use some basic script.  Something like:

 

private onTime = 30 * 60 // 30 minutes * 60 seconds per minute

private offTime = 3 * 60

private totalTime = 48*60*60

private startTime = systime() // get currentTime

while (systime() < startTime + totalTime)

   output = 1 // turn on

   wait(onTime)

   output = 0

   wait(offTime)

endwhile

 

Note that I use wait().  You could use delay() too, but you'll get some propagation (i.e. the actual loop time will be, in my case 3 minutes + 30 minutes + a few milliseconds for the LabJack calls and script execution).  Using wait() eliminates this, though can cause problems in some instances, thus the warning you get.  Not an issue here.

[User123]

Thank you very much. I am using two LabJacks and they typically run at the same time. I have two different sets of outputs (for both sets of instruments). How can I include channel information (i.e. specify which channel this sequence should work on)? 

[AzeoTech]

It'd probably be easier in the long run to just create two sequences.  Its not the best programming technique, but is easier to understand.  It would also allow you to run both loops at the same time.

[User123]

Thanks, I was able to program the sequence.