On Sunday 29 November 2020 22:21:10 Jon Elson wrote: > On 11/29/2020 08:09 PM, Gene Heskett wrote: > > But what characteristic is it that actually determines > > what sort of a servo it is? As in torque vs velocity? I > > intend for this to work under cutting loads. That is why > > the double reduction of two worm drives in series that > > this will be. > And this has an encoder generating good quadrature signals optically, on the back end of the motor, from which the encoder module will output both position in counts (for comparison to SCALE) and velocity. Can I use both signals in 2 pid's in series? I've seen that mentioned in some of the searched for links with the claim that its much more stable that way.
> A velocity servo has a speed sensing device (like a DC > tachometer), the control sends a velocity command, the drive > is supposed to make mechanical velocity exactly proportional > to commanded velocity. > > A torque amp has a current sensing device (ammeter shunt) > and the command from the control makes current proportional > to the torque command. Motor torque should be very close to > current except at the outer edges of the motor's curves. And this particular driver doesn't seem to have a usable current sense output. I think it does use it internally for short circuit protection, but at about 10x what this motor draws, about 4 amps at full load. But this BTS 7960 based driver is rated at 43 amps. And has no detectable temp rise running the motor at half speed for many hours, running at a 2 kilohertz & 50% pwm. Pretty good for a $6.17/copy driver. But I can hear the pwm, so I'll probably change that to 4 kilohertz since at 4 kilohertz, the carhart notches in my hearing are 120 db deep. The last time I was tested, the operator turned it up to all the drive her machine had at 4 kilohertz and all I could hear was the white noise of the amplifier. Carhart notches are the result of damaging loud noises, and I've worn out or burned out several rifle barrels in my 86 year history without earmuffs in the early years, and with trees in front of the bench reflecting the supersonic crack back at me from just a few feet. I had my own 85 yard range just past the garage when I lived 3 miles out of RCSD on Nemo Road back in the '60's. Hawg Heaven for a deer hunter. Thanks Jon. 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-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
