How to create an event marker with durations of upto 10mins

[Andy josh]

Hi,

I want to record the time of an event, occuring on the acquired data or a user generated keyboard event, since the start of a recording sessions. A typical session of record will take 10-15 mins. The timer need to start as soon as the recording is initiated and run without overflow till end of recording.
So my two problems are:
1. How do I create a timebase for the counter so that its TC duration will be atleast 15mins and at the same time be able to detect 10ms event.
2. How do I connect the above timebase to 2nd counter, which will read the time of event, and read the count value and store in an array when an event occurs.

Any help or guidelines to approach this problem will be a
ppreciated

[Filipe A.]

Andy;

If you are using Labview to do that, you can take advantage of the shipping example named "Measure Buffered Period.vi". You can set that counter's source to be the 100K interanl time base, and route the events line to that counter's gate pin. At each event, the counting number will be stored at the buffer, and you can keep reading those numbers. as you know the frequency of the timebase, the elapsed time will be the counting number you read, times 1/100k. As you probably don't need much accuracy on the 10minutes counter, you can do that opeartion by Software, and stop the while loop after that time has been reached.
Hope this heslps.
Filipe
Applications Engineer
National Instruments