Count digital events on a Counter with pci-6602 with callback on CVI

Question

Hi,
I'm using a PCI-6602 card with CVI 8.5 and I need to trig on event.
On every pulse I received, I need to do some actions like increasing a counter, send a message on Rs232 etc.. I don't want to do any loop checking that the counter value has changed. I would like to use a callback to execute this code only on the edge or counter value event.
My problem is that I don't know which function can do this. Is there any way to get an event on a pci-6602? 
 Thanks 
James 
Solved!
Go to Solution.

Answer 1

Hello.
It's completely possible to create a callback that will allow you to do what you want when a edge will occur on an external signal you define.
To do this, you can for exemple create a counting edges task that will use one of the 6602 counters,and the set your external signal to be the source of your sample clock.You'll then be able to register a callback with the function DAQmxRegisterSignalEvent, and your callback will be called each time an edge will occur on your specified sample clock source.
Here's 2 links that explain the events in DAQmx and how to handle them in CVI. The example ReadDigChan-ChangeDetectionEvent.pr that ships with DAQmx examples (Hardware Input and Output<<DAQmx<<Digital measurements) can be very useful to understand how to do. This example creates a signal event callback to detect change detection for digital inputs.
Regards.