Flow Meter Amplified Square Wave Measurement using NI 9361

[MShinn1]

I am purchasing a flow meter that outputs a 12 VDC amplified square wave in order to measure the flow of a fluid. I will be using a NI 9361 module to measure this signal. I want to confirm that this is the correct module to use for this type of signal output. Furthermore, could I use this module to measure other waveforms such as a flow meter with a sinusoidal wave output?

[GerdW · Accepted solution]

Hi MShinn,

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@MShinn1 wrote:

I am purchasing a flow meter that outputs a 12 VDC amplified square wave in order to measure the flow of a fluid. I will be using a NI 9361 module to measure this signal. I want to confirm that this is the correct module to use for this type of signal output.

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Yes, the NI9361 is able to read pulses with upto 24V in differential mode as written in the manual.

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@MShinn1 wrote:

Furthermore, could I use this module to measure other waveforms such as a flow meter with a sinusoidal wave output?

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The NI9361 expects "digital inputs" (like square waveforms) as written in the manual. A sinusoidal waveform is not digital…

But you can always use your own signal converter (aka comparator circuit) to convert that sinusoidal signal into a digital one. I do that for most of my counter tasks to improve the signal integrity (aka SNR) and to prevent wrong behaviour of counter tasks…