I'm making a printer to mark large parts. I've already got the printer head but i need position feedback for the program so it knows where it's printing. I need 24/0v output from the encoder with 20 pulses/mm. does anyone have some suggestions?
A low cost 400PPR quadrature encoder would need to be on a 1/4" or smaller pulley, which is unlikely. You'll probably have to look at the more expensive 2500PPR encoders, which could use 40mm pitch diameter pulleys and get right around 20PPMM. A slightly smaller pulley, say 32-35mm, would guarantee you the accuracy. A 2000PPR encoder may be a little cheaper, and put you in a similar ballpark for pulley sizes. But you'll have to calibrate the system regardless, because even if you set up everything to get precisely 20PPMM, it's almost impossible that it'll be 20.0000PPMM, and you'll get cumulative errors.
goo point, i should clarify it's a minimum of 20 pulses/mm. i can tell the program how many there are to the nearest whole pulse. this doesn't require incredibly accurate printing. i'm a beekeeper and i'm looking to barcode my jars, i can tolerate 5mm error over .5m so being off 1 pulse won't make a big deal. hopefully there's something <$200 available. there are several 'cheap' ones but they're 5v, not 24.
Anything industrial grade will be 24V tolerant, but getting it below the $200 mark can be tricky. Any quadrature output encoder should produce essentially the same results, though, so trolling eBay should yield something usable. Depending on on your anticipated running speed and its resulting signal frequency, you're likely to be able to find a level shifter that can operate quickly enough to interface with 5V devices as well, which may be the cheaper option overall.
