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Hi Ian,


Sorry, but it’s not working yet. I can’t change the driver, although there is a message that says the driver has been successfully switched, it is not changing. If I access again later, it continues NI-DAQmx Base, I don’t know why. I have tried with the two NI-DAQmx that appear to select.

I also tried what you told me in the Front Panel but it doesn’t work either.

I print you some screenshots if they can help to solve this mistery.

Many thanks



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Message 11 of 20

Hi Vicente,

The front panel change won’t have any effect until we get the device working in DAQmx rather than DAQmx Base. So let’s try and get the device working in DAQmx:

Best of Luck,


Message Edited by Ian Colman on 10-24-2007 03:14 AM

Message Edited by Ian Colman on 10-24-2007 03:14 AM

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Message 12 of 20
Hi Ian,
I think it's working now, at least there are no errors when I run the program. I haven't checked it yet sending a pulse but I'm optimistic. I hope now it will work. If I have any other problem I will contact with you. Many thanks for your help, it has been very useful.
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Message 13 of 20

Hello Ian,


I have USB 6501. I used this for counter to have a simple counting event. This is to replace my old DAQ AI-16XE-50. I developed my counter with Measurement Studio ver 8.6. I have read the example of vb net for USB 6501 with new Ni-DAQmx driver. However, it have to use the call back and synchronize functions.


Do we have some thing more simple way to access the value of counter by calling directly?. If it is, I need example of code or document.


I have seen that Ni have a lack of organize to support software develop to the specific hardware product that they sale. User must have to find this place to looking for the simple problem that should not be wasted.


Thank you for your help,


Tu Nguyen


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Message 14 of 20

Hi Tu,

Good Morning and I hope your well today - thanks for the post.


I am afraid Ian has moved on from NI but NI UK Support has notified me of your post. 


A lot of the events (callbacks as you've named them) are for the user front panel. If you wish to just the read the value of the counter you need to use the counter setup code and then 

just read using,


myReading = myCICounterReader.ReadSingleSampleUInt32()


One of the events  loopTimer_Tick is for the timer on the front panel - if your using the hardware clock then this would also be different.


Is the example  your looking at, CountEvent from the vb net examples?


Hope this helps,

Kind Regards
James Hillman
Applications Engineer 2008 to 2009 National Instruments UK & Ireland
Loughborough University UK - 2006 to 2011
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Message 15 of 20

Hello, NI experts,


I would like to detect the first few pulse of a digital signal in real time, is USB 6501 counter good enough for this end? I tried the example count digital events, but the counter is not stable, sometimes the counter just stuck there, and even worse the computer is dead.


Could you please give me some directions/suggestions? Thanks a lot,



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Message 16 of 20

Hello Deliang,


the USB6501 counter is software timed, so it is not good enough for real time applications.

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Message 17 of 20



do you have any suggestion for real time application?





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Message 18 of 20

Hi Deliang,

sorry, I don't have experience with real time applications, so I can't give you any hints.


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Message 19 of 20

Hello Hilman,


Thanks for your help. However, I need to find the complete example how to use ni usb 6501 for counter's functionalities such as start counting, stop counting, reset, initial the number to counter, read current counter.


I found that the class task can be control for start and stop but I could not find how I load the certain number to counter register before starting count.


My application is to use this device as simple counter for wheel encoder to have trigger on certain distance of vehicle.


Thanks for your help.



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Message 20 of 20