What sensor should be used to measure speed of motor

[Ayaz]

Hi,

I am using NI PCI-6624 to control the speed of dc motor. I have used "PWM-Counter Output.vi" example to generate PWM pulses to control the input power of motor. I am using "counter output" and "analog input" terminals of PCI-6624. Counter output terminal is used to generate PWM signal and "analog input" terminal will be used as an input from speed sensor.

Can someone tell me what sensor I can use to measure the speed of motor. Please note that the output of the sensor will be the analog input to PCI6624, so it is essential that speed sensor's output is ANALOG.

Please help me in this matter and tell me which sensor can be used and from where I can buy it ?

Thanks

[Ayaz]

CORRECTION:- I am using NI PCI-6224 rather than PCI-6624.

[Jochen]

Ayaz,

the straight forward low-cost solution for velocity measurements is using a quadrature encoder. With your  DAQ device you could use the second counter of the board to measure the frequency of one phase, but that's jus one option amongst others.

I haven't come across sensors that output a voltage that is proportional to velocity but expect such a device to be much more expensive and probably less accurate.

Do you plan to do closed loop velocity control? Are you using Windows or a realtime system?

Kind regards,

Jochen Klier

National Instruments