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Re: Hall Effect Sensor.
Kevin,
The data sheet is really vague on this question. I have not used these sensors but in reading the data sheet, it repeatedly talks about how the duty cycle is fixed at some value and is stable with respect to temperature, air gap, and speed. I found that there is some hidden text as respect to duty cycle in the sheet and the waveforms for duty cycle are missing. (search the pdf for "duty cycle" and at the bottom of p8 you will see highlighted blanks, I selected the text and pasted it in another document to read it.)
Due to the variations in tooth shape, tooth depth, surrounding metal, etc., I believe the magnetic fields vary considerably. I am guessing that the manufacturer tried to compensate for these variables and probably aimed for 50% +/-5% by sensing zero cross. There is discussion that the sensor learns it's environment over the space of 64 cycles, adjusting gain and A/D parameters to make the output stable and accurate.
If anyone has practical experience with this device and can produce a waveform or two, it would be a big help. I will try and dig one out and see if I can get some data, next week. FLL state tournament is this weekend, so it's going to be pretty busy between now and then.
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Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
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Storming the Tower since 1996.
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