Re: How to use Digital output to turn on sensor for Analog Input?

[Bill B]

Hello,

Thank you for contacting National Instruments.

If you are worried about the time of your acquisition being off, then
you should associate each voltage measurement with a timestamp.  This
will allow you to know the exact time at which the sample was taken
and you will never be off.  You can use the Get Date/Time in
Seconds.vi in our while loop with your AI code so that you can read a
sample and read the time.  You can than log the voltage value and the
timestamp to your file.

Regards,
Bill B
Applications Engineer
National Instruments

How to use Digital output to turn on sensor for Analog Input?

[mooseo]

I am trying to use a digital output to turn on an array of sensors
that I then wish to read on 16 analog input lines.  I have a 6024E DAQ
card.  I am planning to take data at 10-20 hz, so not terribly fast,
but I will be acquiring for long periods of time (days) so I will be
streaming data to disk.

I have a fair bit of experience in Labview basics, but can quickly get
out of my depth when I try something new (like this).  I have V6.01.

It looks as though the best way might be to do the DO and then a
single AI as individual events, then write to disk and continue
through the loop.  I am puzzled, however, how to keep this cycle on
schedule given that I don't know how long it will take to sample 16
channels, write the data to disk and get back to the starting point...
perhaps this is so fast that I don't need to worry about it?   The
actual timing of the samples (be it 10 or 20 hz) isn't too critical,
as long as I can record at what time they were taken... it would be
frustrating to find that I was several seconds off after days of data.