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Non-stop movement between G0/G1 commands

Posted by umod.47 
Non-stop movement between G0/G1 commands
February 05, 2019 07:04AM
Hello.
I'm trying to use Marlin for a CNC task with 3 motors.
As long as I see, Marlin always comes to full stop at the end of G0 or G1 command.
I'e. if I send the following:
G0 X0
G0 X100 F1000
G0 X200 F2000
Marlin will travel from X=0 with speed 1000, decelerating to 0 at X=200 and accelerating to 2000 afterwards.
Is there a way to skip this stop, so Marlin reaches the point X=100 at speed 1000 and then accelerates further to speed 2000?
Of course, the following command should already be buffered.

Thanks.

Edited 1 time(s). Last edit at 02/05/2019 07:04AM by umod.47.
Re: Non-stop movement between G0/G1 commands
February 05, 2019 06:19PM
I suggest reading the wiki. It explains the difference between G0 and G1 commands, which may explain your issue.


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Re: Non-stop movement between G0/G1 commands
February 07, 2019 05:26AM
RTFM was the first thing to do smiling smiley
[marlinfw.org] - for example.
Marlin documentation states the same as wiki: there's no difference between G0 and G1 commands regarding movement.

Please pardon me if the question is placed on the wrong forum, but I haven't found any other forum about marlin firmware.
Re: Non-stop movement between G0/G1 commands
February 07, 2019 07:39AM
your description doesn't compute

G0 X0 <=== move to X0 at what ever was the last feed rate set.
G0 X100 F1000 <==== move from X0 to X100 at feed rate 1000 mm/min
G0 X200 F2000 <==== move from X100 to X200 at feed rate 2000 mm/min
<==== no more command, once at X200 everything has stopped

Are you saying it stops at X100 ? As that is not normal behavior
perhaps you should look at your jerk setting
#define DEFAULT_XJERK 20.0

And yes in reprap G0 and G1 are identical, Both run the same piece of code.
Re: Non-stop movement between G0/G1 commands
February 07, 2019 12:37PM
Not exactly.
[www.youtube.com]
This is what i'm talking about. The g-code executed is just like posted.
The printer reaches X=200. But it decelerates to full stop at X=100 and then accelerates back.
Replacing G0 with G1 doesn't change anything.
Re: Non-stop movement between G0/G1 commands
February 07, 2019 08:19PM
As already stated, that is not normal behavior...

what have you done to the configuration.h

Edited 1 time(s). Last edit at 02/07/2019 08:19PM by Dust.
Re: Non-stop movement between G0/G1 commands
February 08, 2019 06:19AM
Nothing specific.
Hardware setup is Mega 2560 + RAMPS 1.4, the default one for Marlin.
configuration.h got changed a little: endpoints, number of steps per 1 mm, axes sizes. Just a minimum amount of changes for the printer to work fine.
I'm using pronterface to control printer and send g-code.
Acceleration was specially lowered to see this stop. This is the g-code used (it is printed in the description of youtube video):
M201 X25
G0 X0
G0 X100 F2000
G0 X200 F4000

Anyway, if the printer is not supposed to stop completely, but still decelerates between these movements, this is not a desired behaviour.

Edited 1 time(s). Last edit at 02/08/2019 06:20AM by umod.47.
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