Triggering two conuters with two digital signals

Hi,
i am doing some period measurements using a 6221 M-Series card with two counters.
My problem is now to trigger them with two different digital TTL signals. How can i do this?
(Period times Signal 1 <-> Trigger 1, Period times Signal 2 <-> Trigger 2)
Has someone an example vi?
regards
Jens

Here you can find an example, that shows how to use a trigger for a counter. It is not exactly what you want, but shows the rigth way. Hope it helps:
http://zone.ni.com/devzone/cda/epd/p/id/1612

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