On Saturday 12 September 2020 07:46:05 andy pugh wrote: > On Sat, 12 Sep 2020 at 05:19, David Berndt <ber...@uberwin.com> wrote: > > 2) Is there a minimum value for G93 feed rates. > > Not as far as I know. I just tried a test move of G93 G0 X100 F0.01 > and it moved 1mm in 1 minute. > > > rotating A axis with something like G93 A45000 Z-1 F.2. > > I tried this G-code in the axis-9axis sim. It complained that there > was no movement mode active. Putting in a G1 I got approximately the > expected result, in that Z moved 0.5mm in 4.5 minutes. So I assume > that the A axis was maxed out in the simulator. > Bumping up the A axis max speed from 90 to 360 gave me a system that > did 25 revolutions in 1 minute. > > Had you done a G0 move? > > G0 X0 Y0 > G93 A45000 Z-1 F.2 > > Moves very fast. As G0 is modal. This ought to be an error, I think. > (G0 X0 Y0 F10 is accepted. It is valid G-code but probably isn't what > anyone intends. It says "set the feed rate to 10 and then perform a > rapid move") > > G93 with G0 active, however, clearly makes no sense and appears to > cause confusion. From this Doc quote:
• G93 - is Inverse Time Mode. In inverse time feed rate mode, an F word means the move should be completed in [one divided by the F number] minutes. For example, if the F number is 2.0, the move should be completed in half a minute. When the inverse time feed rate mode is active, an F word must appear on every line which has a G1, G2, or G3 motion, and an F word on a line that does not have G1, G2, or G3 is ignored. Being in inverse time feed rate mode does not affect G0 (rapid move) motions. I think it should throw an error for a G0 on that same or previous line hat updates the modal to a G0. And a "G93 A45000 Z-1 F.2" won't run on the G0704 whose A axis is a slow worm drive, throwing an instant f error but, it appears to run as expected on the 6040 whose A axis is belt driven and capable of several rps. Wall time for that command is exactly 5 minutes, but I preceded it with a g1f20x0y0. Rehomed, and xy zeroed with a g0 is not an error but the reported z velocity is not .2, but 1.92, crazy fast. I think it would be helpfull to issue an "educational" error as its not really a valid command for the G0 mode. As it will quite likely break the tool, it shouldn't be allowed to run IMO. My $0.02. 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