Way back in 2003 I started a project to control the surplus tread mill motors I had acquired. At that time I was still just casting parts for making my Gingery Lathe and thought about making my own DC Servo motor controller.
http://www.autoartisans.com/MotorDrives/MOTOR1-5.JPG The first prototype had a bunch of problems and then regular paying work took over, I needed the bench space and never revived the project. http://www.autoartisans.com/MotorDrives/REVA0059.JPG The controller was the MC33030 http://www.autoartisans.com/MotorDrives/MC33030-D.pdf Knowing what I know now I'd never use this device but back then... John > -----Original Message----- > From: Thaddeus Waldner [mailto:thadw...@gmail.com] > Sent: October-18-20 11:23 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] driver for a DC motor for a BS-1. > > > 1. direction changes are slow. No consequences when driven by the human > > hand running a joystick on the side of the seat, but important for > > computer control. > > Typical delay for changing direction is 600microseconds. This is less than > the typical LinuxCNC servo period of 1ms. The reason for > this delay is probably due to the relatively slow switching speeds of the > high-side mosfets, to eliminate shoot-through. If you plan > to change motor directions no faster than the LinuxCNC servo thread, why is > this too slow? > > This is too slow to drive the motor in "synchronous antiphase� or with a > triangular waveform but I don�t get why you want to do > that. But there are many things I don�t get. :) > > > 2. No evidence from the waveforms shown that the pwm is used for anything > > but a logic clock. At no point in the waveforms shown starting on page > > 13, is there any evidence of the pwm actually modulating the outA or > > outB voltage in time with the input pwm. This is designed as an on/off > > control only, and low standby current consumption in the very low > > microamps was the prime specification driver. The boards I have ordered, > > unless they are doing something that STM does not know or show, are not > > capable of pwm driven analog control. > > As per the timing diagrams, the PWM input directly controls the low-side > power mosfet with a 1.5 to 5 microsecond rise/fall time. > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
