About measurement method

Question

Hellow!
Normally speaking,when taking a waveform measurement by labview,is it necessary to take a new measurement continuously(put the read waveform.VI in a While loop)? or just take one measurement each time? thanks!

Answer 1

Hi.
LabVIEW does not limit you in the method that you chose for
acquisitions.  The method you chose should be determined by your
application and what you are trying to do.
If you have an application in which you want to be continously
acquiring until you reach some stop conditions, then you should have a
VI resembling the continuous acquisition VIs found in the help (like
Cont Acq&Graph Voltage-Int Clk.vi, which is a very good
example).  Notice that in the examples you do NOT read 1 sample at
a time, but with each iteration of the while loop you read several
samples, making the acquisition more computer-resource efficient.
If you have an applicaiton in which you previously know how many
samples you will need in total, then you do a single 1-run acquisition
of all the samples you need.  A good example of this is
Acq&Graph Voltage-Int Clk.vi, also found in the VI examples that
ship with LabVIEW.  If the number of samples you need is fixed but
very large, then you might have to do a merge of the 2 VIs to avoid
overflowing the buffer.
There are a few applications which do require to read 1 sample at a
time, like control applications, in which you need to react and
generate a response to each individual input sample.  Those
applications usually have the configuration VIs for both the analog
input  and output operations outside a while loop and the read and
write VIs inside the while loop.
Hope this helps.
Alejandro