FPGA on cRIO

[sidpen]

Hi

I have a NI cRIO 9066 with 9401 modules which I am using to try and control a Pololu 100:1 Metal Gearmotor 37Dx57L mm with 64 CPR Encoder. I am trying to use the encoder outputs to calculate the angle/position. I have seen examples of angular encoders on DAQ devices. I am trying to find one to use it on FPGA. Are there any such options? I have attached a picture of a DAQ example I looked at. I also looked at other forum posts on this topic but they were not very helpful or I couldn't use the advice.

Thanks

Sid

[GerdW]

Hi sidpen,

AFAIK there are example VIs showing how to create encoder counters using simple DI pins with an FPGA.

You just need to check for rising/falling edges on your DI signals and use them to count the encoder pulses!

[sidpen]

Hi GerdW

I did try to do just that and I have attached an image of the VI I used but I am getting wrong results. The image shows my two encoder inputs (DIO1 and 2) that I am counting to get total encoder pulses per revolution. But I am getting far more than the 6400 pulses I should be getting per revolution.

[TimothyDug]

Hi sidpen,

Have you seen this document, specifically #3 where it mentions configuring your encoder application on a cRIO?

It also mentions using DAQmx tasks, but this will not be possible with your cRIO 9066. That is a new feature offered with our 904x chassis, such as the cRIO 9045.

Let me know how that works for you!