G38.x and acceleration (not stopping)
03 Jun 2016 12:38 #75405
by arhi
Replied by arhi on topic G38.x and acceleration (not stopping)
not working 
the "syntax" goes but it ain't doing nothing
and the g-code:
all three moves are using exactly the same acceleration the acceleration value is not changed
the "syntax" goes but it ain't doing nothing
arhimed@linuxCNC:~/linuxcnc/nc_files$ cat ../configs/mill25d/custom_postgui.hal
sets spindle-at-speed true
net X-accel motion.analog-out-00 => ini.0.max_acceleration
net Y-accel motion.analog-out-01 => ini.1.max_acceleration
net Z-accel motion.analog-out-02 => ini.2.max_accelerationand the g-code:
G17
G21
#<_X-Accel-original> = #<_ini[AXIS_0]MAX_ACCELERATION>
#<_Y-Accel-original> = #<_ini[AXIS_1]MAX_ACCELERATION>
#<_Z-Accel-original> = #<_ini[AXIS_2]MAX_ACCELERATION>
T1
M6
(DEBUG, "default accel move")
F500
G1 X50
G1 X10
(DEBUG, "no accel move")
M68 E0 Q9999999
F500
G1 X50
G1 X10
(DEBUG, "slow accel move")
M68 E0 Q1
F500
G1 X50
G1 X10
(DEBUG, "restored accel move")
M68 E0 Q#<_X-Accel-original>
F500
G1 X50
G1 X10
M2all three moves are using exactly the same acceleration
the acceleration value is not changed Please Log in or Create an account to join the conversation.
03 Jun 2016 12:49 #75409
by arhi
Replied by arhi on topic G38.x and acceleration (not stopping)
had to try 
unfortunately looks like no way to change those values
unfortunately looks like no way to change those values
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03 Jun 2016 12:53 #75412
by andypugh
You can change them, then run a program. You just can't change them while a program is running.
Try issuing the commands from MDI.
Replied by andypugh on topic G38.x and acceleration (not stopping)
had to try
unfortunately looks like no way to change those values
You can change them, then run a program. You just can't change them while a program is running.
Try issuing the commands from MDI.
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03 Jun 2016 12:55 #75413
by arhi
Replied by arhi on topic G38.x and acceleration (not stopping)
will try that ... should help with G38 thing but not with everything else I wanted to use it for
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03 Jun 2016 12:57 #75415
by andypugh
I am still failing to see why, if your Z-axis can achieve a higher acceleration than you have configured, you don't simply set the Z axis to use the high acceleration all the time?
Replied by andypugh on topic G38.x and acceleration (not stopping)
will try that ... should help with G38 thing but not with everything else I wanted to use it for
I am still failing to see why, if your Z-axis can achieve a higher acceleration than you have configured, you don't simply set the Z axis to use the high acceleration all the time?
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03 Jun 2016 13:09 #75417
by arhi
Replied by arhi on topic G38.x and acceleration (not stopping)
not that simple, my axis can deal with high acceleration up to a certain speed... for e.g. I can drive XY @F500 without any acceleration (my original 3d print firmware don't support acceleration at all) but over F500 it will skip steps .. I need this "jerking" moves (infinite acceleration) while 3d printing in order to "break the string of plastic" so for some moves infinite acceleration is required, for some other moves the acceleration is required as higher speeds are achieved that way .. also I want to have a slow speed move with infinite acceleration and high speed move with regular acceleration... I can have 2 heads in the same time, one depositing plastic, other one depositing silicone, while I'm depositing plastic I have a stepper driving the extruder so acceleration on all 4 axes is working ok and in sync, on the other hand for silicone I have on/off pressure valve and constant extrusion rate so can't have acceleration on the XY axes, it has to be uniform from start to stop, yes that requires slower move but it works .. now since the idea is to use both heads in the same print - first the plastic head make a scafold for few layers then silicone head fills it I need to be able to change acceleration mid print (hence those M20x codes I mention we normally use on printers) ... now for milling I doubt this is needed but I would like to move my printing to linuxcnc as well as I'm sure printing would benefit from better speeds I see linuxcnc is able to achieve (looking forward on how pats look like and adapting speed in corners etc..) + changing reconnecting motors from linuxcnc box to a reprap box is crap I already replaced 2 connectors
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