Pulse time measurement?

[jonasz]

Hi,

I'm pretty new to data acquisition with NIDAQmx and LabView 2009 (specifically, we have a 6323 card); I've tried to find a solution to my problem online but haven't managed to find the right thing (or to recognize it). We want to process the occurrence of digital pulses on at least one channel. Pulses will be about 100us long, and time between pulses can range from 1ms to >>1s.

I've had a look different approaches: I can measure pulse periods, but so far I haven't been able to extract information about the time between start of the pulse and the actual processing.

I guess another way would be to have a counter run and count cycles between edges. I've tried this in SignalExpress but it puzzled me that I got the same number of ticks for all the samples I collected in one iteration. I wonder whether I did the right thing there (I set up a pulse generation task on one line and counted these pulses). Then of course I still have the problem of knowing at which tick I am when I process the data.

I would be very grateful for any hint (or pointer towards a document where this has been discussed).

Thanks,

Jonas 

[falkpl]

look at the continious semi-period buffered counter input task.  This will give you both the high and low times for each pilse, I think this is what you are asking for.

[jonasz]

Paul, thanks for your reply.

However, this is not exactly what I'm looking for. I'm more interested to know the precise timing of the events relative to the time I read out the buffer.

Thanks,

Jonas

[Christian_Hartshorne_NIUK]

Hi Jonas,

I have been searching through various online resources for a document or example which may help you with this application but I have not managed to find anything which specifically addresses your requirement. What I would say is that generally, whatever you application (particularly for DAQ applications) there will usually be an example in the NI Example Finder which illustrates the key concepts. I have found some examples which are applicable under the Hardware Input and Output > DAQmx > Counter Measurements > Period and Pulse Width category.

It may be that you can take one of these examples as a basis for your application (which you will then need to modify or add to) or you may be able to combine features from different examples.

I hope this helps.

Best Regards,

Christian Hartshorne

NIUK