Further investigation produced this document: http://www.wallacecompany.com/cnc_lathe/Servo_Schem.png
, which seems to indicate that, these are indeed analog input servo amps. On Tue, 2007-06-19 at 21:30 -0500, Jon Elson wrote: > Kirk Wallace wrote: > > Thanks for the replies Jon and Ray. Like Ray said, I was wrong about the > > servo drivers, they have PWM inputs instead of the analog inputs, which > > is even better. So it looks like the Universal PWM controller would be a > > better fit, plus it has the DAC option for the spindle VFD. It would be > > nice to have another for the three phase coolant pump VFD too. > You want a variable-speed coolant pump? That's one I've never > heard of, before! I brain faded there for a while. I believe I was thinking about a VFD as a three phase converter, but in this case, I would only need a digital output. > I will > > need more digital outputs. Another printer port may do the trick here? > Yes, you could do that. You can get about 11 outputs and 3 > inputs, I think. > > Each axis and the spindle have a tachometer and a resolver. I am > > planning to replace the resolvers with encoders, but is there any reason > > to keep the tachometers? Removing both, plus the gearbox they are > > mounted to, would free up space for a proper encoder, it seems. > OK, now you have a contradiction. If the motors have > tachometers, that implies a velocity servo amplifier. That > would have a +/- 10 V analog velocity command to program axis > velocity. You say the servo drivers have a PWM input. Are you > sure of this? Just because the servo amps use a PWM technique > does not mean they accept a digital PWM signal. There is a > remote possibility the tachs are used for machine safety only, > but I would give that an extremely low probability! The tachometers are connected to the servo drive, so they will be needed, if I decide to use these drives. Performance-wise, does anyone have an opinion on whether to stick with the existing velocity amps (which overall will cost more) or go with new torque-mode PWM amps? > If you replace the velocity servo amps with torque-mode amps, > then you can remove the tachometers. > > Jon ... ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
