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Need guidance: NI-9401 with two 18,000 CPR encoders?

Looking at the 9401 specs, superficially it looks as if this will work. I am looking at using two rotary encoders, each the same with 4500 PPR/18,000 CPR. Each will also have an index track. The shaft speed will be a maximum of 7,150 rpm. That is 7150/60*4500*2=1,072,500 digital switches per channel per second, well within the 9 MHz signal switching frequency (because I will be using six channels). I do have higher resolution choices available with these encoders (the RLS MR series and LM10 series read heads) which I would like to use if I can.

 

I am assuming the "Maximum signal switching frequency" on the 9401 spec sheet is the maximum allowable incoming signal frequency, and not how fast it is scanning for the input.

 

In the end, I am going to connect two of these encoders, each with an A and B channel plus an index to one 9401 in our cRIO. We will do our FFT and everything else after the fact.

 

Is there something I might be missing or does this make sense?

 

Thanks for the help -

 

Chris P.

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Makes sense to me.

9 MHz input frequency of NI-9401 should meet your requirement.

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Applications Engineer | TME Systems
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