Analog Period Measurement in FPGA

[WYL]

My project is using sbRIO with C-module 9225E to capture analog signal with voltage swing between 0 to 60 Vdc. Need to measure the frequency of the signal, there are 2 approaches:

1, I prefer to use Analog Period Measurement.vi to retrieve signal value from one of the ports of 9225E to generate period which I can use sample rate to calculate frequency. (attached Target_GetPeriods.vi)

2. signal values from 9225E are read into FIFO and then use target to host DMA to send data to host.  Host will have to use sample rate to loop time and scale period.vi to get frequency value. (attach SM_3secft_M1_3_display.vi)

Could both approaches work?? In first approach, I am concern about if Analog Period Measure.vi able to measure such a high voltage signals and what is the maximum signal strength it can handle?

Thanks.

[WishKebab]

Hi WYL, 

The Analog Period Measurement VI simply compares the input values to a specified threshold.  The values coming from the 9225E will simply be a numerical representation of the voltages read at the input terminals.  The NI 9225 is designed for a maximum voltage range of +/- 300 V, so you should be good to go.  Your second method would also work.