Use of a non-NI DAQ with Labview

[Mystery]

I am attempting to use a Measurement Computing PCI-DAS1200 with Labview. I setup the Instacal program that came with the card and it also gave me Labview drives for the card. The drivers were auto-installed. The MCA icon shows up in Labview on the block diagram listings but I cannot seem to get the card to output a signal. Windows clearly recognizes that the card is present but is there something extra that I need to do to make Labview accept the card. Is it possible that I have to configure the card in Labview somewhere like with the DAQ assistant?

[Brent_D]

First, be sure you have installed the "Universal Library for LabVIEW", which is part of the MCC DAQ software suite from Measurement Computing Corp.

Now how to get started ... This posting should be sufficient to get you up and running with the Measurement Computing Example VI's. This covers all the steps after installing InstaCal and the Universal Library for LabVIEW.

Launch InstaCal to detect your device and assign it a board number.
Note the board number, it will be used in a future step.
Close InstaCal.
If InstaCal is left running, problems could be encountered in LabVIEW.
Launch LabVIEW
Using the example browser, select Folder View or browse the hard drive. The examples will be located in the following directory.
C:\Program Files\National Instruments\LabVIEW 7.1\Examples\Universal Library\ (the path may vary with different versions of LabVIEW and where you installed LabVIEW to)

All Measurement Computing Corp. (MCC) examples begin with "x" (example: xAIn.VI)
All of the MCC VI's that are used in the examples are found under the User Libraries in the function pallette of the block diagram. These are the only VI's that are supported when accessing MCC hardware.
If you are running into problems with the hardware or need to reconfigure it, make sure that LabVIEW is closed before making any changes in, or opening InstaCal. The driver will still be loaded in LabVIEW and will not notice the changes that are made. Once you make your changes in InstaCal, and close InstaCal, then you can restart LabVIEW.

Note: If you get messages about missing VI's when loading a program that was created to run with an MCC brand DAQ device, make sure the Universal Library for LabVIEW is Installed. Then locate the das16.llb in the <LabVIEW>\menus\Universal Library\ folder. All of the VI's are contained in the das16.llb

[Agnivesh_Kumar]

I am also using same DAQ card and my card is working properly . but when i acquire the signal then some samples are lost suppose i acquirning the signal for 2 second with the sampling rate of 50KHz then it should have to give 100000 samples but it will give 80000 samples . so i am loosing the samples why this problem came sir?

[Brent_D]

It is not clear if you are using the now legacy (frozen) UL for LabVIEW, or the newer ULx for NI LabVIEW driver, but neither should lose data.  The PCI-DAS1200 is a mature PCI board, which does not have driver support for Win-64.  Though I'm sure you are not on a 64-bit O/S, since the card is recognized by InstaCal.  If you are using the legacy driver, and you are performing background+continuous, then likely the data is being overwritten in the Windows buffer before you copy it out.   Try instead the ULx driver, which is a higher level driver that will move the data for you.    If you are truly losing data, the issue is likely PCI bus related.  Either the board is bad, or there is an IRQ conflict with another device on the bus, or perhaps a threading issue with multiple CPUs.  Try moving the board to a different slot to get a different IRQ level, or turning off all but one CPU/core in the BIOS.

[Agnivesh_Kumar]

Sir  ,

I am using Window XP and Labview 7.1 .

For this there are universal library and using the Background operation i got the signal correctly but when i record the samples then there are loose of samples. my DAQ card working properly i think Problem is with my program i am also sending you my program. please see and made correction if you feel .

Thanks For relpy .

[Dennis_Knutson]

Duplicate post.

Do NOT ask the same question to multiple boards

[Brent_D]

I have looked at your attached VI.  It uses our legacy driver's foreground mode, not the background mode as you said.  But perhaps that is good news, since Foreground is what I call "foolproof", since none of the data is available for graphing/disklogging until all data is collected.

Your VI does not specify default values for # of samples (count) or sample rate (Hz).  But, I think I know what your problem is.  You have a timeout in the loop which is probably stopping the loop too early, before all data is written to the file.  The time it will take to collec the data (for a single channel) is (count/rate) plus some overhead.  We don't specifiy the overhead, which will be PC dependent. 

[Agnivesh_Kumar]

Sir what is the solution for this?

[Brent_D]

In my last posting, I gave you advice to get rid of the loop timeout.  Have you tried that?   In fact, get rid of the entire loop, andjust collect one arrany of data.  If no data is lost, then the problem is solved.  If you cannot find the solution, you should upgrade to LabVIEW 8.5 or later and use the newer ULx driver.

[Agnivesh_Kumar]

ok Sir,

But if i remove the while loop and loop time out then when i run the program it will run only one time. So how can i know that for how much time my program run means for 1 sec or 2 sec .... so on . and how i know that the samples i got are right. main thing is time.