On Saturday 24 August 2019 12:46:28 John Dammeyer wrote: > > > I already have my mill running with a single parallel port but the > > > single phase motor is still controlled with a switch because I'm > > > too lazy to temporarily wire in a relay. What I do have for my > > > mill is a sweet Bergerda 1.8kW AC Servo that works very nicely > > > with step/dir signals and has a 2500 line encoder (10,000 pulses > > > per rev) which means it needs more than the parallel port can > > > deliver. > > > > Yes, that encoder will run out of bandwidth trying to get thru that > > bobs opto-iso circuitry. So you are out the cost of at least a 5i25 > > which has at least 100x more bandwidth at its encoder inputs. I've > > had to cut and bypass the opto crap on the bobs several times now. I > > am a CET, but many machinists far more capable than I at turning > > cranks, wouldn't feel comfortable doing such hacking. > > Actually not a problem. Especially for the spindle.
Thats 10k edges per rev, and 3000 revs, that 300,000 edges a second, and right at or slightly beyond the bandwidth you can shove thru an opto-isolater. Expect problems John. Here on the g0704, I have a 1000 line encoder on the rear of that 1hp 90 volt motor. At 1500 spindle revs, the multiplier is just above 14000/rev, so the input to the encoder is coming in at 21,750,000. Its been run thru a couple rs-485 convertors, but the 5i25 is not haveing problems with it. Which amazes the heck out of me. But mama says shes hungry, and see that famous sign. Back eventually. > The drive also > has a numerator/denominator step multiplier on the input. I tested > this by replacing a smaller DC brushed servo that has a 250 line US > Digital encoder (x4=1000 per rev) and set the numerator to 10. It was > plug and play at that point. Nothing changed with the hal or ini > file. Just a smaller AC servo running the X axis. Sweet > > And I can also program in a numerator/denominator pair on the encoder > outputs. So I can make the motor encoder appear like one that has 200 > pulses per rev. Aside from the poor manual I'm really liking the > Bergerda AC Servos. I may be ordering some more in the near future. > > > > So that means > > > a Smooth Stepper and MACH3 or the MESA 7i92H which is the cheaper > > > option and plugs directly into my existing BoB. (part of the > > > criteria). > > > > I'll have to look at the 7i92. Just did, wouldn't consider it as it > > would tie up the single net port on most motherboards. I consider a > > working network a requirement and all my machines can browse the > > net. > > It's pretty inexpensive to order a second Ethernet Board. I have one > but the bracket is for full height mounting. I need a short one for > this PC. > > > Take care John. And I'm sure I'll learn something from it. > > I'm definitely learning a lot from trying all these different motor > drivers. The one I haven't tried yet is the Gecko DC Servo drive. I > have two of those that will probably just be sold. Now that I've > played with the physically smaller drives that only need 220VAC input > and not a separate power supply I can't see using the Gecko. My DC > Brushed motors are 90VDC. I'm using 2 of Jon's (pico systems) pwmservo drives against 90 volt motors, with supplies in the 127 volt range, and limited to 17 amps or so. So the 1hp is probably twisting close to 2 hp. They seem to love it. > The Gecko can't go that high. The next > power supply I have is 60V for the knee stepper motor. I'm now > thinking about how I'll change to the AC Servo for that. Haven't > bothered with the quill. It's locked fully up for now. > > Thanks for the feedback Gene. > John > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
