Basic Rundown of Digitial IO Techniques with Examples.

[Blah!]

Hey Folks:

   I seem to be orbing around a solution to what I need, but always run into an error, that it seems nobody else is running into. I think I'm missing something.

   Trying to do digital input with DAQ-mx on a PCIe-6535B   along the following lines.

Data -----  X_BE56_X_78CD_X_FFE2_X .........

Strobe _____----_____-----_____----___  .........

I'm sending the strobe into PFI5 and the data are going into data ports 0 and 1.

I'm getting a errors along the lines of data timeouts etc along the lines of

DAQmxErrorCannotReadRelativeToRefTrigUntilDone                             (-200281)

 I don't fully understand what DAQ-mx input modes are and I can't find a full write up that goes into depth on all the modes and how they work.

Also it seems that DAQ-mx is self contained. I can't find any write ups or examples on how to size buffers and transfter acquired data into arrays and files so I can actually do something with the data.

I'm using the canned examples, I've attached one, but there's very little explained here. Does anyone have any pointers?

Thanks

Andrew

[fblerg]

Hi Blah!

It seems like that error is related to how you are triggering the acquistion. You may want to continously acquire data and then post process or process data based on the Strobe line. The DAQmx Configuring Logging function in the example does log data to file. You will just have to change the Logging Mode control to Log and Read instead of Off. Please take a look at some links for more information on DAQmx.

Timing and Synchronization Features of NI-DAQmx

http://www.ni.com/product-documentation/4322/en/

How Is the DAQmx Buffer Size Allocated for a Finite or Continuous Acquisition?

http://digital.ni.com/public.nsf/allkb/E1E67695E76BA75B86256DB1004E9B07

Retriggerable Analog Voltage Acquisition

https://decibel.ni.com/content/docs/DOC-11757