Qns on DAQmx function

i am currently using ATMI force and trying to use VB6 to get the reading for the six analog channel in realtime..
I keep seeing ppl use daqmx function.. but i dont have that in my library... i have install NI -DAQ 7 and measurement studio..

Do any one have program that run muti analog channel by not using daqmx.. using traditional code

Similar Messages

DAQmx function blocks missing from Labview palette

Hi,
I have just finished installing labview 2012 development suite to my current computer including NI-DAQmx 9.4. I have done this in the past and had no problems, this time however when I open LV the DAQmx function blocks are not available to me despite everything else being there and functioning correctly including the Measurement and automation software.
I have gone through and checked to make sure that I included all components of the software and its drivers. Is there anything that I may have overlooked while doing this install that would cause the DAQmx blocks to be unavailable to me.
Thanks.

Did you install DAQmx before or after LabVIEW? If you installed before, you need to reinstall DAQmx. It won't take long. It just needs to add the LabVIEW support.
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Daqmx functions generate a waveform

I need to use the daqmx functions to generate a waveform. The waveform specifications...
Square wave...min voltage 5V, max voltage 8V...50% duty cycle...2kHz frequency...run continuously.
What daqmx functions do I need to use to generate this square wave? If this has been covered in another thread, I apologize.
Jeremy

Hi jjsomer,
There are a couple of example VI’s that you can use for that, you can go to the NI Example Finder » Hardware Input and Output » DAQmx » Analog Generation » Cont Gen Voltage Wfm-Int Clk.vi
That VI will show you how to output a signal that could be sine wave, square wave of saw tooth wave. In order to set the parameters that you need, you can use the Square Waveform.vi instead, this can let you set an offset for the signal.
I hope this will help you,
Regards,
steve.bm
AE | NI

How to define in different controls device and channels in a DAQmx function?

Hi,
I need to build a vi that permits the user to change the device of a DAQmx acquisition system, although I don't want that the user modify the input channels. I`d like to know if it is possible to define in different controls device and channels.
[]´s
Juliana

Hello Juliana,
What you would like to do is possible with some simple string manipulation. First you will need a Device Name constant from the DAQmx >> Advanced >> DAQmx Constants & Property Nodes palette. Right-click on the constant and turn it into a control. Then, use a concatenate strings function to join the device name with the rest of the characters you need to define your input channels. Wire the output of the concatenate strings VI to your DAQmx Create Channel VI.
Let me know if you have any questions on this.
Thanks,
Laura

Understanding DAQmx Functions

Hi ,
I have a few questions regarding the DAQmx Library in CVI.
1.While working with DAQ Devices I'm opening a Task and a channel to some device For example AO1.
I'm setting it to work with an external hardware trigger and defining all the needed parameters , starting the task doing the analog output and stopping the task.
so far so good , but if I want to repeat the same task without setting all the parameters again how can I do that ? Does the device remember it's configuration ?
the thing I need is to make a task that will repeat it self for days with out setting parameters because it takes time from each test, time I don't have.
2.NI Function time cycle , is there any document that show how much time it takes for each function ?
3. DAQmxErrChk (DAQmxCreateAOVoltageChan(gAOtaskHandle,AOchan,"",AOmin,AOmax,DAQmx_Val_Volts,NULL));
the values for AOmin & AOmax : if I'm setting it to -10 : + 10 , is it possible to change it with out creating a new channel ?
Kobi Kalif
Software Engineer

While I have no idea about your second question, I suppose you can use DAQmxSetChanAttribute with DAQmx_AI_Max and DAQmx_AI_Min attributes respectively. I have no DAQ device at present to make a real test and see if changing these attributes with the task started raises any error or actually does not changes settings at all (that's why I didn't post this before), but you can try it in minutes.
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Using DAQmx functions without installation

Good evening everybody,
I have an instrumentation problem linked to DAQmx. I would like to communicate with an instrument using NIDAQmx tasks. I use an environment program system : visual studio 2003. At the end, I want to produce a dll. This dll, I want to put it on another computer. The question is the following. If I want to launch the dll by calling it, will I need NI-DAQ on the other computer or a software to use the dll ?
When I tried to produce an exe with a VI, I needed to have Labview RunTime to launch the exe. If I want to launch the dll, will I be able to use the dll alone on the computer, without the installation of NIDAQ. Can I use the tasks only with the dll (since I need Run Time for the .exe, do I need Run Time also). ?
I am sorry, it must be not clear. But I am available to explain you more the problem.
Best regards.
Thank you.
gautier
Solved!
Go to Solution.

Since you have LabVIEW installed on your computer, the Run-Time is not required for running LabVIEW executables.
But if you decide to use your LabVIEW executable on an other computer, you will need to install the LabVIEW Run-Time on it. You can also build an installer which will contain your program and addtionnal components (such as LabVIEW Run-Time and required drivers). Building an installer avoid to download and install the components separately.
For more information regarding installer, you can look into LabVIEW's help (Building an Installer (Windows)) or follow Core 2 training course.
If your program uses NI-488.2 driver, you will need to install it on your computer.
Installing LabVIEW Run-Time is only required if your program which contains DLL calls is a LabVIEW executable.
Regards,
Jérémy C.
National Instruments France
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Simultaneous tasks using DAQmx functions

Hi all,
Is there any example of DAQmx PCI-6251 on Labwindows in which Multithreading is used.
Basically i want to acquire and generate Analog signals from PCI-6251 by using Multithreading.
In which one Thread is for Acquiring the analog signals and the other thread is for generating
the analog signals after performing some calculations on the samples of the Acquired Signals.
So it means i dont want to Acquire and Generate analog signals Simultaneously but there must be a
"Little Delay" between the two Threads.
Any help on this topic will be Greatly appreciated.
Regards

Actually, this is entirely possible. The primary difficulty is sharing data between your two threads. The easiest way to accomplish this in LabWindows/CVI is with a thread safe queue.
I admittedly don't write much DAQ code, so it likely won't meet your specific needs, but I've attached a simple example of doing what you've asked about. I create two threads, one for reading and one for writing. Each thread creates a task, and then loops while reading or writing until told to stop. They share data through a thread safe queue.
Let me know if you have any questions regarding the sample -
NickB
National Instruments
Attachments:
DAQMTProcessing.zip ‏7 KB

Modifying Daqmx Function Generator

hi everyone,
I found an example from ni and I want to have it modified a little bit. I need to add delay before and after generating the sinewave in 1 channel, how to do that? Just simply delay, sinus, delay.
Then I need to have range of control for the delay (the delay can be 1ms ~ 1000ms), is that means I should use small buffer (1ms) to be able to vary the delay? (but seems buffer 1ms doesnt work).
Please help.
regards,
yan.
Attachments:
funcgen.png ‏112 KB

hi,
I really appreciated your VI, thanks for that.
I made my own VI already, a little different concept, but working.
You might know about error -200018:
"A DAC conversion is started before the data to be converted were available.
Decrease the output frequency to increase the period between two DAC conversions, or reduce the size of the output buffer to the data faster (faster) to write.
When using an external clock, check whether the signal contains noise or voltage spikes."
I got this error when I try to acquiring the generated signal at the same time I'm generating. Can't find any help or solution for that.
regards,
Yan.

Pretriggered plus posttriggered Using DAQmx functions

Dear Sirs,
In the propel.vi which is attached, laser is used in the channel Vi0 to start the mechanism of trigging to acquire posttriggered samples from the analog signal in the channel Vi1 successfully. I would like to know what changes I need to do in the block diagram to acquire pretriggered plus posttriggered samples from the analog signal in Vi1?
Thank you for your help.
Oscar Delgado.
Attachments:
propel.vi ‏34 KB

Hello Christian,
Thank you for your reply. According with your suggestion I found in the examples file of my LV the Cont Acq & Graph Voltage – Analog SW Trigger.vi, which I am using successfully to acquire pre triggered plus post triggered samples.
Thank you for your help.
O. Delgado.

What is the equivalent function of NIDAQYield in NI-DAQmx?

I have to migrate from traditional NI-DAQ to NI-DAQmx for Window 7 64bits system. I like to find the equivalent function of NIDAQYield in NI-DAQmx?

As far as I can see here, NIDAQYield is simply a way to process system events, so I suppose calling ProcessSystemEvents () will be equivalent to calling it.I do not know of a native DAQmx function that does the same. It is to be said, though, that DAQmx way of handling acquisition process is different from Traditional DAQ one and direct translation is not always possible, so depending on how you migrate your code, calling those functions may be unnecessary.
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Why does using the NI-DAQmx ANSI C functions in a thread cause a deadlock?

First up, apologies if this is the wrong board but it seemed the closest fit.
I'm using MSVC 2008 Express with the NI DAQmx ANSI C library to perform some analogue output using a USB-6009. I am creating a thread to handle the generation of the signal as it is on a fixed timebase. My main thread runs the user interface. I have found that I get intermittent deadlocks in release mode while the NI libraries are being loaded (in the second thread) and I use some MSVCRT functions (on the main thread). My test code is attached as "deadlock2.cpp".
I have used WinDbg to try to find the cause of the deadlock. The stack traces of my two threads are attached as t1_stack.txt and t2_stack.txt.
It appears that the localtime() function from the MSVCRT uses a lock when it is called for the first time and then goes to lock the Windows DLL loader lock. At the same time the NI libraries (or at least mxs libraries) are being loaded so the DLL loader lock is being held. The mxsutils library uses getcwd() which appears to try to lock something in the MSVCRT and so my two threads are now deadlocked.
I can probably work around this by calling the localtime() and the NI DAQmx functions before I spawn my second thread so that the DLLs are already loaded into the process. However, I have no guarantees of this continuing to work if anything changes in the future, and if there are any locks going on then having the DllMain() called for a thread attach may still cause a deadlock. If my findings are correct is it likely that NI would fix the DLLs to not try to do anything complex in their DllMain()?
According to NI Measurement and Automation Explorer I'm running v9.3.5f2 of the DAQmx libraries. I'm downloading the latest version now to try but it will take some time.
Solved!
Go to Solution.
Attachments:
deadlock2.cpp ‏2 KB
t1_stack.txt ‏2 KB
t2_stack.txt ‏3 KB

Hi dmcminn,
Thank you for the detailed and complete bug report. I was able to reproduce the problem with NI-DAQmx 9.6 using the code you posted. I reported it to the appropriate R&D team as CAR #366538.
I agree with your analysis of the problem. Both getcwd() and the first call to __tzset() acquire _ENV_LOCK, which Microsoft has documented as the "lock for environment variables". __tzset() also calls GetTimeZoneInformation(), which may load additional libraries, as you have shown.
Here are a couple more potential workarounds, but they're not great:
Link to the static version of the CRT (/MT instead of /MD). This would link a separate copy of the CRT lock table into your program, and DAQmx would continue to use MSVCR90.dll's lock table. They would no longer use the same _ENV_LOCK.
Build using a different version of Microsoft Visual C++ (e.g. 2005 or 2010). MSVCR80.dll, MSVCR90.dll, and MSVCR100.dll own separate copies of the CRT lock table.
Either way, it doesn't eliminate the fact that mxsutils calls into the CRT while holding the loader lock, and that CRT function acquires another lock.
By the way, the Multifunction DAQ forum is a better place to post DAQmx questions.
Brad
Brad Keryan
NI R&D

PCI6602 functions in DAQmx

I have been using PCI6602 in NI-DAQ for a long time. Recently I upgraded to DAQmx. The standard tasks such as frequency measurement is very simple in DAQmx. But for special needs, I can't find the corresponding functions as in NI-DAQ such as selecting source and gate signal. Furthermore, I can't find the detail explanations of DAQmx functions in DAQmx Help, such DAQmxCfgSampClkTiming() in the ANSI C examples.

I am glad that you decided to upgrade to DAQmx! You will be very happy about it once you get used to the new functions available. The C reference help is located in:
Start>>Programs>>National Instruments>>NI-DAQ>>NI-DAQmx C Reference Help
This is where you can find all the information on the functions and properties in DAQmx. Also, there are C examples for DAQmx located in:
C:\Documents and Settings\All Users\Documents\National Instruments\NI-DAQ\Examples\DAQmx ANSI C
Regards,
Jordan F
National Instruments

DAQMx Write und read function

Hello,
I want to use DAQMx functions for my projekt.. but I do not understand one thing. Wenn I have a differnet Input should I use DAQmx write and for the Output DAQMX Read? or better said what is the different betwen DAQmx write and Read, When I can used write and read?

Hi nichts,
use the DAQmx read function, if you want to acquire a signal from your card. If you use a differential input, you also use the same vi (DAQmx read) and change the "input terminal configuration" on the DAQmx Create virtual channel vi to differential mode.
If you want to generate data from your PC and output those data over your DAQ-Card, use the DAQmx write VI.
If you use the DAQmx driver the first time, I would recommend you the following internet page:
Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications - Developer Zone - National Instruments
http://www.ni.com/white-paper/2835/en
You will find all necessary information about the important part of the DAQmx driver on this page.

Nilvaiu.dll functions

HI. I am trying to get the list functions of nivaiu.dll library. Does anyone know the the nivaiu.dll programming manual or related information.
Thanks
Gary

Hi Gary,
Thank you for your question but I am a bit uncertain if I have understood it correctly. From my understanding, nilvaiu.dll is a DLL that is built in to DAQmx. Is the issue then that you are missing the DAQmx functions? If so, it could be that your copy of the drivers are corrupted and I recommend reinstalling them. You can access them here.
Kind Regards,
Shalimar Ali
Applications Engineering Intern

How do i pass a daqmx task from labview to matlab using the math interface toolkit?

I want to use DAQMX functions from Matlab using the Math Interface Toolkit (MIT). How can I have a labview function output (return) the DAQMX task to matlab via the MIT?
I want to do this so I can start a DAQMX task in Labview from a matlab function and return control to matlab without losing the task.

Hi Mark,
(I already posted this answer in your other thread, but let's keep THIS thread alive - it makes more sense here in the LabVIEW forum than in Instrument Control forum.)
Since the DAQmx Task is not a native data type that can be passed directly to MATLAB from LAbVIEW, try flattening the DAQmx Task to a string before passing to MATLAB. However, I doubt that you can access the task from within MATLAB, but feel free to give it a try.
Good luck!
- Philip Courtois, Thinkbot Solutions

Qns on DAQmx function

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