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How to configure digital filter for pci 6601

I want to add filter to my counters inputs because there is noise in my input : I have trouble in measurement of quadrature encoder with 6601.
I must use I/O Config Register, Pins A through D , Input Select <2..0> but there is no exemple for quadrature encoder.  How can I implement this function?

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Hi SteFaNy,


What kind of noise do you have?

Is your application in polluted environment (presence of motors, electromagnetic waves...)?


You can use a digital filter to remove any bounce at the output of your encoder. If this is not enough, I invite you to create a filter to remove spectral components that are the problem on your encodeur.

Access to the digital filter is via property node as shown in the link below:


Enabling the Digital Debounce Filters for TIO Devices in NI-DAQmx


You can find several exemple from the tool "exemple search" of labview with the déscriptions: "measure angular position"



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Hi Stefany,

There is an example for quadrature encoders in the DDK -- gpct_ex7.cpp -- and it uses the default values of the I/O Config Regsiter -- all zeros -- which means that the pins are input-only and are unfiltered. If you would like to enable the digital filters, refer to the documentation for the I/O Config Register in the NI 660x RLP Manual [1]. By setting in the Input Select field to non-zero values, you can enable different digital filters. The manual also describes reading quadrature encoders in Chapter 2, page 2-9 (which is page 26 of the PDF).

[1] NI 660x RLP Manual

Joe Friedchicken
NI Configuration Based Software
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