Can I measure the fan speed by NI 9401 & cRIO 9075 under Scan Interface?

[William1225]

Hi,

I'm currently using NI 9401 & cRIO 9075 to develop a project, that is to control the CPU fans.

Since I have to communicate with other instruments by serial port so that I have a module of NI 9870 to implement the instrument control.

I've finished the instrument control part under scan mode, and would like to add the function of reading fan speed.

Now I wonder if there is some problem when I choose the Scan Interface to deverlop the program.

I found the following tutorial that it uses the FPGA interface to impement the PWM control and frequency acquisition.

http://www.ni.com/white-paper/3230/en/

So if the function of fan control is only developed under FPGA interface, I have to rewrite the instrument control part, seems to be a little complicated...

[William1225]

It seems that it is only to be implemented in the FPGA interface if I'd like to control and measure the CPU fans.

Because the frequencies of the PWM signal of interest ranges from 25KHz to 100KHz, and the PWM frequency configuration is limited in the scan mode... http://digital.ni.com/public.nsf/allkb/0892C8D55C6D0C0E86257585004FD0B0

So... I've given up to develop my project in the scan mode to control and measure the CPU fans...

[OA1 · Accepted solution]

You can use hybrid mode.

http://digital.ni.com/public.nsf/allkb/0DB7FEF37C26AF85862575C400531690

[William1225]

Hi OA1,

Thanks for your suggestion, that's what I need.