Voltage Pulse to RPM

[Marshman]

Hello,

I have a speed sensor that senses a notch in a motor shaft.  When the notch is sensed, a 5V voltage pulse is sent to my NI cDAQ-9171.  Does anyone have a good idea how to program LabVIEW to convert that 5V voltage pulse into a RPM measurement?

Thanks

[KoenR94]

You could use peak detection, then convert the time to rpm.

[Marshman]

Could you provide a sample code?  I understand what you are saying, I am just having difficulty seeing the program

[moderator1983]

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@Marshman wrote:

When the notch is sensed, a 5V voltage pulse is sent to my NI cDAQ-9171.

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NI cDAQ-9171 is 'NI CompactDAQ 1-Slot USB Chassis', what I/O module are you using for your application?

[Marshman]

I have a NI 9923 connection for a 37-pin DSUB module

[moderator1983]

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@Marshman wrote:

I have a NI 9923 connection for a 37-pin DSUB module

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This is also not an I/O module, but this is just a Front Mount Screw Terminal Block for 37-Pin D-SUB Modules.

[Marshman]

NI 9207

[Marshman]

Here is the code that I have started.

[moderator1983]

Ok, so you're using an analog input module.

1. Calculate the frequency of acquired signal (in Hz).

2. Multiply it with 60 and thats the RPM.

[Marshman]

Yes, I agree. My question really is how do I obtain the frequency?