LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

PDA Host USB (Solar Express CF Card)

Solved!
Go to solution

Ed,

My problem was due to my not entering the name of the physical device correctly.  Your code works OK with the 6009.  Just had to enter device as "Dev1/ai0" (see help for Create Channel VI, if you have similar issue).  I am not very familiar with the Dynamic Tasks, but this now works well.

 

The card also works with the 6215 (supports Dynamic Tasks only).

 

Al

0 Kudos
Message 11 of 13
(1,079 Views)
I got it to take data.  It is really slow, though.  I was expecting some higher throughput, but maybe I have to tweak things out a bit.  If I tell it that I want 5 samples per channel at a rate of 10 samples per second, and send the data to a Waveform Chart, it only seems to update about once a second.  Is that a limitation of Charts running on a PDA - update speed limitation?  I have some other programs running with the CF-6004 compact flash DAQ card and they update the chart a lot quicker.  Maybe I'm doing something wrong, or, like I said, I need to do some more tweaking.  I was really looking for the chart to update as fast as the data was coming in.  I have not yet written any data to disk, or tried to use the 6008 with my laptop, but these may allow me to figure out what's going on.  I have attached the exact VI, in case anyone wants to try it out.
0 Kudos
Message 12 of 13
(1,072 Views)

Ed,

 

What you are trying to accomplish is continuous samples.  What you have in code is finite samples.  Every time that while loop executes, it must create the channel, set up parameters, take the data, log the data, then remove the channel from memory.  This is where the delay is coming from.  You need to make this continuous samples, and put only the read in a while loop.  There are a plethora of examples in the example finder to demonstrate continuous acquisition.

 

Reading 5 samples at 10hz should update the graph twice a second. I know of no limitations on the throughput, but I am still playing around with this card myself.

Rob K
Measurements Mechanical Engineer (C-Series, USB X-Series)
National Instruments
CompactRIO Developers Guide
CompactRIO Out of the Box Video
0 Kudos
Message 13 of 13
(997 Views)