Datalogging Hall Sensors via a PicoScope

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Datalogging Hall Sensors via a PicoScope

Post by Guest » Wed Jan 28, 2009 5:28 pm

Good Evening All,

I'm currently trying to understand whether one of the PicoScope products will fulfil my needs.

We have an electrical motor with two hall sensors, currently the sensors are floated at 12VDc and as the motor rotates it pulls them down by approximately 0.5V to 1V

The motor operates over a minimum time of 1 second with anything up to 5 Seconds possible dependant upon speed. During these time periods we expect to see 400 hall counts from each sensor or 800 in total.

So from my calculations (please someone correct me if I'm completely wrong here, it's been a while!) we have a maximum 400Hz signal. Which would need to be sampled at 800Hz according to Nyquist. However as the pulse widths vary, I think a sample frequency of at least 2000Hz would be required.

Currently I'm using a Tektronix scope which is severely limiting in that it can only sample a maximum of 2500 points at a time. At a sample rate of 5KS/s (2500HZ max signal resolution) this only gives me 0.25s per channel of recording before it retriggers and uploads the data to Signal Express. It is at this point I'm losing data.

So my question is, can you recommend one of the PicoScopes that can sample at 5KS/s (Or 4KS/s) on both channels for at least 5 Seconds? And am I correct in my calculations?

Kind Regards

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Post by Autonerdz » Wed Jan 28, 2009 11:58 pm

A 3424 or 3423 would sample at 333.3 KHz on each of four channels with a 5 second capture time.

10.42KHz with a 200 second capture time. :shock:

Tom Roberts
(The Picotologist)
skype: autonerdz
THE PicoScope Automotive Authority
In North America

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