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 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!
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
