I have two shafts rotating from about ~200RPM to ~1500RPM. They normally rotate at exactly the same speed. I need to detect when one shaft rotates at a different rate than the other shaft. I don't need to know the actual speed of the shafts, just the difference.
Waaaaay back, this was done with Selsyns attached to the shafts which worked great. I don't have the luxury of attaching anything to the shafts except maybe some striped tape for an opto sensor to see, or maybe some magnets for a reluctor to sense.
I could build two F/V converters and compare their outputs, but the slightest drift from either one will throw my readings out of the window.
I think a digital approach is the best bet but I can't wrap my head around comparing two inputs at such low frequencies (~4 Hz).
Any ideas?
Thanks,
Joe
Waaaaay back, this was done with Selsyns attached to the shafts which worked great. I don't have the luxury of attaching anything to the shafts except maybe some striped tape for an opto sensor to see, or maybe some magnets for a reluctor to sense.
I could build two F/V converters and compare their outputs, but the slightest drift from either one will throw my readings out of the window.
I think a digital approach is the best bet but I can't wrap my head around comparing two inputs at such low frequencies (~4 Hz).
Any ideas?
Thanks,
Joe