On Sunday 13 September 2020 04:53:39 David Berndt wrote: Back to the list too.
> Ok, I wasn't around yesterday to read the replies and do more testing. > > My previous g-code example had some artistic license applied as I was > not at the console to copy the code and was a bit lazy, plus I hoped > it would be reasonably clear. Lets ignore the fast rotary axis, that's > really not what anyone cares about here. Also yes I forgot the G1 in > the example, but as I was getting different results for various values > of F then it seems to me there would have bene no way I was testing > without the G1, a G0 would always run at the maximum speed. I'm short > a time machine to go back and look at my initial testing instructions. > > > Here's an actual real world test I just ran. I manually transcribed > this as annoyingly you can't seem to copy out of the MDI history > window when the machine is in e-stop. So there's my get out of typo > jail free card again. > > G0 Z-6 A0 > G93 G1 Z-6.1 A360 F10 > G93 G1 Z-6.2 A720 F5 > G93 G1 Z-6.3 A1080 F2.5 > G93 G1 Z-6.4 A1440 F1 > G93 G1 Z-6.5 A1800 F.5 > G93 G1 Z-6.6 A2160 F.1 > > Expected speeds of the A axis as per the axis.N.joint-vel-cmd and move > time: > F10 - 60 deg/s - 6 seconds > F5 - 30 deg/s - 12 seconds > F2.5 - 15 deg/s - 24 seconds > F1 - 6 deg/s - 60 seconds > F.5 - 3 deg/s - 120 seconds > F.1 - 0.6 deg/s - 600 seconds > > Hopefully we're agreed on the theory? > > My results: > > F10 - 60 deg/s > F5 - 30 deg/s > F2.5 - 15 deg/s > F1 - 6 deg/s > F.5 - 6 deg/s > F.1 - 6 deg/s > > > -Dave Thats certainly odd. If there is not a minimum speed set someplace, I am out of clues. If there is one set, then that limitation should result in some error output because its preventing G93 from doing its job. Do you get anything on the terminal screen you started linuxcnc -l on? > On Sat, 12 Sep 2020 10:43:30 -0400, Gene Heskett > <ghesk...@shentel.net> > > wrote: > > 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 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
