On Sunday 11 February 2018 20:12:12 jeremy youngs wrote: > http://ebay.com/itm/LJ12A3-4-Z-BX-Inductive-Proximity-Sensor > These were the winner in the opening comment. They have a five pack > for less than$20 which would leave 2 left over . Their mounting would > work well with a tone wheel on my spindle . My > Drive runs a tach and this would be a good solution for spindle index > as I have no great place for an encoder.
I didn't either, so I drilled and tapped the rear of the motors shaft, which was sitting flush with the top of the rear bearing, and made a 5mm extension about 10mm long that fit the omron encoder's 5mm coupling. Made a square hole in the top cover and mounted a 1/8" alu plate about an inch above the top of the cover to mount the encoder itself on. Sounds rather like apple tree mechanics, but its working quite well. 2 of those, if they are fast enough would work well with a tone wheel, but the low speed performance would suck. The problem there would be the low tooth count of the tone wheel. My combo of using the old interrupter index against an encoder on the motor is that the scale count per spindle rev is quite high, over 7000 in high gear, and over 14000 in low gear, but some tally switches on the shift knob and some hal magic fixed that right up. That speed overpowered the opto's in the bob, so they've been excised. The encoder didn't say, but when it arrived it was differential outputs, so some dollar a copy rs485 gismo's were used as receivers. Works fine to the spindles max of 1500 or 3000 revs which is a hair over 350 kilohertz at the 5i25 inputs. I think they'll work fine for an index, but I'd have reservations about using them for the encoder A/B generators. As for the drive (I'm assuming a vfd) having a tach, its probably derived from the frequency being sent to the motor, meaning its going to be a few percent optimistic with a load on the motor. They always have a slip angle, its what makes the motors work, so a 4 pole motor at rated load, running on 60 hz, will actually be turning between 1725 and 1750 as opposed to a fully sync motor which would be doing the full 1800 at light load. I'd much rather have proof of the spindles absolute position everytime an edge of the tone wheel goes by. This is working so much better that the 67 slot opto disk in the g0704, that given enough time before I miss morning roll call, I will do the same for the teeny motor on my HF micromill. Except that's a good excuse to put the bigger 400 watt motor I took out of TLM when it grew a 1 horse drive parts breaker. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
