Synchronizing start of counters for period measurement

[Carsten Buchloh]

I am using PCI-6602 counter card (which is replaced by a PCI-6624 in a few weeks).
Programming is made with C/C++ and DAQmx 7.2.

The task is to measure period and semi-period time of 4 digital signals continuously.

I need the relationship of these 4 signals additionally, so it is important, that the counters will be started synchronously.

I have tried 4 tasks for each counter and I am using thefollowing functions for the synchronization:
DAQmxSetDigEdgeArmStartTrigEdge
DAQmxSetDigEdgeArmStartTrigSrc

Arm Start Trigger Source is a digital input.

Are these functions correct for my task?

If yes, what is the correct order:
Do I have to start the 4 tasks with DAQmxStartTask(..) and then set the Arm S
tart Trigger Source?

This seems not to work, the counters start counting even if the trigger source is not set.

Thanks for each helpful answer.

[bestin]

Use the property node to set the trigger source and trigger source. Call that before arming the counter. it will explained on the example files. look under the example file called count digital evants-pause trig