On Wednesday 28 August 2019 22:22:09 John Dammeyer wrote: > Gene, > > You've got it backwards. The parallel port version is correct which > is why that line is there. > > > > setp parport.0.pin-07-out-invert 1 > > setp to 1 is also true, setp to 0 is false. It may be right or wrong, but one of them should reverse the signal anyway.
> > remove the above line, or set it false > > > > > net zdir => parport.0.pin-07-out > > Peter Wallace suggested I do this: > "If you are using LinuxCNC 2.8 you can set the stepgens dir polarity > parameter." > > Can't find a "dir polarity" parameter here: > http://linuxcnc.org/docs/html/drivers/hostmot2.html#_parameters_3 > > However there is an "invert_output" parameter. Which must be setp true (or 1) to be effective. Using true/false makes for an easier read file by a future-you I think. > Still nothing I can > find online really guides me in the direction of doing it with port > inversion or how to use that invert_output since the dmesg > instructions in the above web link don't help. > > However the other suggestion from Peter which was to set the stepgen > scale to minus. Did that to both Z and Y axis and now homing works. One can also reverse the motor direction by swapping (interchanging) either the A wires, or (but not both) the B wires at the driver to motor joint. Usually on the drivers output connections. To further confuse things, the search_vel and such in your .ini file can also be reversed by a sign change. Way too many places for it to bite you. Direction control by swapping motor wires, or changing the sign of the scale is generally done so the keyboard movement is like moving a hole in the direction of the keypress. An uparrow typically pulls the table toward you, moving the "hole" to the rear of the table. A right arrow press should move the table left, effectively moving the hole to the right. Conversely a page up raises the quill or lowers the knee while a page down lowers the quill or raises the knee. I get those right before I start sprinkling minus signs around in the search_vel boxes. This also tends to reduce the surprises between gcode generators and machine movements. > I suspect because the parallel port implementation always reported > "unexpected real time delay" on start-up that it wasn't able to > actually keep up with the acceleration parameters in the .ini file. You do have some pretty brutal settings, jerking the machine around a bit. I'd cut the starter vels by 2/3rds as the more gentle acells will get you faster rapids. > Now with the 7i92H, the acceleration on the Z axis is way too high for > the Gecko run stepper motor. It's not losing steps but doesn't sound > happy. A bit of tweaking with values and it's much smoother. Gecko's I have zero experience with, but I've heard rumors of early capacitor failures. You may want to get an ESR meter and survey them for high ESR'S, anything over 100 uf that reads over an ohm of ESR is suspect. Over 2 ohms, replace. > > I've also played around with the Y axis acceleration since it too has > a lot of mass to move; not only the X axis but also the X axis table > rotation mass. That's why the DC Servo has 4:1 instead of 3:1 > reduction like the X. Max ipm is therefore 120ipm for Y and 150ipm > for X. For the knee with the Gecko and 3:1 to the bevel gear I get > 24ipm. Any higher than that and the stepper will skip. > > The backlash compensation is also far harsher. A series of jogs in > the same direction create almost no vibration on the head of the mill > (hand placed against it) but change direction and my hand feels the > bump as the backlash is first taken up. This was especially > noticeable on the knee with the slight bevel gear connection to the > knee screw until I dropped acceleration to a much lower value than I > had on the parallel port version. > > The 7i92H requires the STEPGEN_MAXACCEL to be double the > MAX_ACCELERATION. Setting it lower than that caused strange motion > problems so I suspect the only way to get rid of the hard bump as > backlash is taken out is to also reduce axis acceleration. > > Or buy ball screws which is on the list... > > John > > > > > > > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
