Count number of turns of low frequency table

[henk1000]

Hi everyone,

I have an application where I need to counter the number of turns of rotary table which spins at around 5 RPM. 

I have LabVIEW and a DAQ USB-6346, but I am not sure which sensor (Inductive, capacitive, etc) to buy. Does anyone have an idea?

[GerdW]

Hi henk,

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@henk1000 wrote:

I have LabVIEW and a DAQ USB-6346, but I am not sure which sensor (Inductive, capacitive, etc) to buy. Does anyone have an idea?

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Whatever fits to your requirements!

Did you write down ALL of your requirements?

Inductive sensors might have problems when your table is made of plastics, while optical sensors might be sensitive to environmental light. You need to consider the size of the sensor and additional sensing elements (magnet, reflector, …) attached to your table. You need to consider the needed power supply for the sensor. Again: write down all requirements!

For simplicity I would use a sensor with a TTL-compatible output and use one of the counter inputs of your DAQ board…

[henk1000]

Thanks for replying. For an inductive sensor I would like to just attached a little magnet to the table. Would you know if is possible to power and measure a sensor with the DAQ?
Do you have a model in mind?

Thank you.

[GerdW]

Hi henk,

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@henk1000 wrote:

Would you know if is possible to power and measure a sensor with the DAQ?

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Read the manual/datasheet of your DAQ device!

The 6346 should come with a +5V pin, and the datasheet will mention how much current you can draw from this pin. When you find a sensor that will run with a 5V power supply then you could use your DAQ device to power the sensor…

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@henk1000 wrote:

Do you have a model in mind?

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No, do some research on your own!

(Are you an engineer?)

[henk1000]

I will have a look on the sensor market. Hope the current from the device DAQ will be high enough to power the sensor.
Thank you.

[jjohn1 · Accepted solution]

Not sure what your requirements are, but it might be as simple as using a reed switch  , a magnet, and some minimal TTL logic (inverter with pullup resistor, etc,).