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
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
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