On 12/8/24 16:54, Viesturs Lācis wrote:
The main place I have used it, is in the spindle speed servo, to soften the turnaround in a rigid tapping operation by limiting the acceleration enough the Z drive could keep up. That pid is probably in velocity mode and I'm not positive I know the difference. Attached is the .hal from that mill. Maybe you can decipher it. What I do know is that the control is stiff, I cannot hear a change in the sound when its getting bogged down before I hear the motor iron chirping because its hit the 18 amp limit in Jon's pwm-servo amp setup. its the usual 90 volt 9.7 amp 1hp motor, but my supply is around 126 vdc. That is a 4 quadrant controller, and bangs the filters up to about 170 volts at turnaround, no heating of the overvoltaged caps, its used to accell the motor in the other direction in 300 milliseconds. From a low gear 1500 fwd to 1500 rev or vice-versa. Been running like that for over a decade. Motor still on its OEM brushes. That's the supply with so much filter uf's I have to slow start it, else it clears a 30 amp breaker in the service. Draws 3A unloaded, 20 at full song. A legal 20 A breaker stays up now. And I forgot, the camera only works occasionally. Every new update to linuxcnc kills it, so I've given up.Viesturssestd., 2024. g. 7. dec., plkst. 00:28 — lietotājs gene heskett (<ghesk...@shentel.net>) rakstīja:On 12/6/24 16:48, Viesturs Lācis wrote:I am fine with workarounds as well. I did find discussion from 3 years ago here on mailing list with a suggestion of putting limit3 component before pid component. That machine has 8i20 servo drives, if that changes anything. pid.n. command is connected to joint.n.motor-pos-cmd at the moment.I'm far from an expert on that but a limit3 has done what I needed several times. And IIRC it has always been applied prior to the pid its controlling,, preferably in such a position as to shape it all in one module.I would like to ask for more details on how exactly to implement this. Since now the pid input is position, adding limit3 does not make sense as I would not control the jerk. I need to change the pid input to velocity. Does it mean that it will change from closing position loop to closing velocity loop? And I will have to redo pid tuning?
Take care Leonardo. Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis
GO704-5i25-7i76-camera-3axis.hal
Description: application/vnd.hal
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