07-07-2010 01:38 PM
I am currently trying to set up a counter to determine the ticks between a digital signal rising edge and an analog signal passing a threshold, but from what I can figure out counter edge measurement doesn't support triggering. I get the error -200452 when programatically creating the task and the triggering tab is not available to start a Counter Edge Measurement in the DAQ Assistant.
I am using an M-series PCI-6220 card so I think it should support triggering, but so far I have been unable to find the correct way to approach this. Can you please tell me at least what type of counter type to use in the DAQ Assistant (or programmatically)?
Thanks,
Andrew
07-07-2010 03:31 PM
Hi Andrew,
Unfortunately, the 6220 doesn't have Analog triggering capabilities--do you have an external comparitor to produce a TTL signal to indicate when your analog signal has passed the threshhold?
Assuming the answer is yes, your best bet is probably going to be using the Two Edge Separation measurement type.
If you are depending on software to make the comparison (which I wouldn't recommend), you can still start the counter task based off of a hardware signal by using an Arm Start Trigger. I agree it's a bit confusing to have two different triggering types for what sounds like the same thing, but Start Triggers are not used for Counter Input tasks.
Best Regards,