How can I start a loop before the DAQ Assistand outputs a value?

Hi everybody,
I created a VI (See attachment) to Measure the speed of a turning wheel. (A optical detector outputs pulses which are proportional to the speed) The DAQ Assistant measures the frequency and the values are written to a log file. To log every 100 ms the value into the table, there is a while loop with should be executet 10 times a second.
The first question:
I want to start measurement as soon as I press "RUN". In fact, my VI first begins to run and log data when the wheel turns and the frequency is not "0". But I want to log data too, if the speed is "0". How can I programm that in Labview?
The second problem:
Labview writes not continuely the values: Sometimes 7 values a second, sometimes 11 values.... (I can see that because i log the time too). But if the programm runs for some seconds its getting better and better.
How can I force Labview to run the loop exactly tacted? Is my Computer too slow? Or is my method to log continuely data simply wrong? I am relative new in Labview and would be thankful in getting help.
Markus
Attachments:
Measure Frequency and Log data.vi ‏63 KB

I would say right off hand from what you describe that the issue is not related to computer speed, but choice of operating system. Windows is not a deterministic operating system - this means you can't count on how long it will take to do anything.
Mike...
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