C# Minimum Pulse Filter for 6601

[mtonsager]

Hi All,

I may have a problem with too many counts coming back from my 6601 counter. I do have a filter setup although I would like someone to look at my code to reconfirm I have it setup correctly.

Here is the code:

countTask =

new Task();

countTask.CIChannels.CreateCountEdgesChannel(grossCountConfig ,

"COUNTIN", CICountEdgesActiveEdge.Rising, 0, CICountEdgesCountDirection.Up);

countTask.Control(

TaskAction.Verify);

countTask.CIChannels.All.CountEdgesDigitalFilterEnable =

true;

countTask.CIChannels.All.CountEdgesDigitalFilterMinimumPulseWidth = 5.0e-6;

myCounterReader =

new CounterReader(countTask.Stream);

countTask.Start();

Just a couple more questions,

Now, when I see "countTask.CIChannels.All", I presume this will filter all the counter channels assigned to this task, right?

Also, I know there is a way to test this filter out, but how would I go about doing that? Would I use some sort of pulse train?

If someone could either send me some C# code or point me to a good example of how to test the filter that would be very helpful.

Thanks for all your help in advance!

Matt

[Ana P]

Hi Matt,

You are right in the assumption that "countTask.CIChannels.All" will operate on all the channels in that specific task. One way to test the filter is by using a pulse train where the pulse width will be smaller than the filter. I see that you are setting up a 5us pulse width filter. I verified in the 6601 user manual that a 5 us filter should block a pulse width of 2.5 us or smaller. So you could test that the filter is working by using a pulse train of 2.5 us width or smaller, in which case your task should not count any edges. I suggested that pulse width because pulse widths between 2.5 us and 5 us may or may not pass depending on the relationship of the pulse's phase and the filter's timebase clock. Unfortunately I couldn't find an example that does exactly what you are trying to accomplish, but there are several C# examples that can give you some ideas on your counter application. These examples must be found in your computer on \National Instruments\NI-DAQ\Examples\DotNET2.0\Counter\.

Regards,

[mtonsager]

Hi Ana,

Thanks for the reply. I don't have the  \National Instruments\NI-DAQ\Examples\DotNET2.0\. folder on my pc. 

Does this come with the new NI-DAQmx 8.6.1 software? If not where can I download this sample code?

I am currently using NI-DAQmx version 8.0.11.12.

Thanks,

Matt

[Ana P]

Hi Matt,

The examples are installed when you install the DAQ drivers. Since I don’t know what drivers you have this knowledge base should be helpful in finding them: Programming NI-DAQ in Microsoft Visual Studio .NET. I hope this helps,