DAQmx read progress

[martym]

I am collecting 5000 samples per channel on 16 channels using the DAQmx VI's.  I would like to have a progress bar that is updated as the data collection takes place.  I have attempted to use the "Current Read Position" property node, however it only outputs the total number of samples taken once the task is complete rather that constantly updating.  Thanks.

[RavensFan]

I don't think you can exactly do what you are trying to do.  As I think you've discovered, the DAQmx read VI is holding until the given amount of sample are read.

A possible work around if you know the number of samples to read and the sample rate is to generate the progress bar in a parallel loop.  Have that loop begin when the DAQ mx read begins.  Let's say you are doing 5000 samples as 50 samples /second., then you know it would take 100 seconds to read.  Use timing functions in the parallel loop to update the progress bar as a percentage of time that has passed.  If your timing is correct, the DAQmx read and the parallel loop should end at about the same time.

[martym]

Thanks for the help.  Using your suggestion, here is what I came up with and it seems to work. The TRUE case just has a value of zero written to a property node of "Progress".

[rpursley8]

Try using the DAQmx Read property Available Samples per Channel.  This will give you the right numbers.  Attached is an example (in LV8.5).  I will also attach a pdf with the block diagram in case you do not have 8.5.


Message Edited by rpursley8 on 01-09-2008 08:00 AM