Synchronized counter and ai measurement with log / different NIChannelLength

[AndrewMc]

For the incorrect data issue, that is really concerning and might require some further exploration.  If you use "Log and Read" mode, are the data values coming out of DAQmx Read correct?  If so, is the data in the file correct in Log and Read mode?  Is there any pattern with where data becomes corrupt?  Do all three files have corrupt data?  Is all the data corrupt or just some of it?  Any additional information you have on this might be useful.  Do you have a small program that reproduces this?

For the triggering behavior, you can find pause trigger in the "DAQmx Trigger" property node.

[AndySchütte]

Hey, I made a "small" program for demonstrate the incorrect data. See attachment. I put the TDMS Data in the ZIP-File for looking at. I moved only x- and y-axis. z-axis was at position 0 (like in TDMS Data). I wrote something in the Documentation of the VI, I hope it helps. The File Data of counters are all and in every log mode incorrect. The Data that shown in Diagram at "log and read mode" and "log off mode" are correct. There seems to be a factor that multiplies to position and TDMS Data goes to a maximum value. For the triggering behavior, I tried to make a pause trigger with an additional "DAQmx Trigger" property node and I got an error (such as "not supported for this device"). I try it later again. Thank you for help. Best regards Andy

[Jan_Wagner]

Hi,

I think something went wrong with the attachments. Can you please post it again?

Thanks!

[AndySchütte]

Hey,

sorry something was wrong. Here the attachment.

Best regards

Andy

[AndySchütte]

Hey,

I tried to use the property node for pause trigger (picture of german version in attachment). I got the Error Message -200452 (picture of german version in attachment).

Did I something wrong or can't I use it with PCIe-6320?

Concerning the wrong log data I did not find out something.

Best regards

Andy

[Jan_Wagner]

Hi,

for your error message i have got the following explanation from the knowledgebase:

Why Do I Get "Error -200452" When I Use Certain DAQmx Properties With My DAQ Board?

[AndrewMc]

Hey Andy,

Sorry about that.  The 6320 apparently does not support a pause trigger.

What about the sample clock signal?  Is it something that could be stopped?  If so, it would help to synchronize them together.

We are currently working to reproduce the wrong data issue and will update you when we have done some investigation.  Sorry for the inconvenience in the meanwhile.

That being said, why are you using Log Only mode as opposed to Log and Read mode?  The reason why I ask is that the performance with "Log and Read" mode tends to be pretty amazing such that the performance difference in "Log Only" mode only becomes necessary for extremely fast rates (for example, >400 MB/s).  I notice in your application that you are reading for -1.  I would definitely recommend that you read for an explicit amount of samples (like 1000).  The performance penalty with reading for -1 can be pretty substantial, especially with logging (since we have to write a new header every time).

[Joe_S]

Hi Andy,

I apologize for the delay in my posting this.  After following along in this discussion thread, I created a VI that tests the function of the DAQmx Configure Logging VI to see if the function will log data correctly.  Using the card I had on hand (PCI-6251) and a DAQ Signal Accessory, my VI creates a counter task to read angular position data from the quadrature encoder on the signal accessory.  If I understand correctly, you were seeing correct data in "Log and Read" mode, but incorrect data in "Log only" mode, which was returning either 0's or -10^7.  After running the VI in both "Log" and "Log and Read" modes and comparing the log files that were generated, the data in the logs are similar, so I do not believe there is an issue with the Configure Logging function.

Note: this test was performed using the latest DAQmx drivers (version 9.3) and LabVIEW 2010.  I have not confirmed this behavior using LabVIEW 8.2 or the version of DAQmx that you are using.  I don't believe it has been mentioned yet in the thread, but what version of the DAQmx driver are you using?  I could test that version to see if the behavior shows up in that version as well.

Regards,

Joe S. 

[AndySchütte]

Hey,

thank you for testing the VI.

I had to take the DAQmx 9.0 (9.0.0f2) driver, because it seems to be the latest, that supports LV8.2.

The TDMS-Data of positions in all log modes are incorrect. Positions I read with "DAQmx read.vi" are correct.

At the moment I read all tasks with "DAQmx read.vi" and write it with "write to TDMS.vi" all data in one file (1000 samples per loop). So I have to reduce the sample clock, because the software depends on the computing power.

Thank you for help.

Best regards

Andy