Configure a buffered counter in python

Hi, 

I'm trying to build an application in python that's very simple. The only thing he has to do is start counting the rising edges on a digital input channel. In the attached python script the counting works, but not in the way I want.

The counting of the edges should be independent of what the python script is doing. In the manual I read something about the buffered edge counting, but I don't understand how to build that.

I'm using the python PyDAQmx library

so please give me a hint how to do it.

Thanks in advance,

R de Vries