Z axis cuts in the air - not plunging

Here is how I have mine set up. Home is at the top and is 0.
bottom of travel is -65

So now jog to top of travel and touch off the Z axis at +65 using the GUI and never touch it again!

I have found this bit to be very confusing but the above fixes it.

Thanks for that will try that later.

One thing i forgot to say earlier is that all axis seem to be tied together - If i change a direction on one it changes the direction on another.
There is only one switch per axis - at the motor end of each way.
All the switches are wired together onto one pin in the controller and I chose 'all homes' in stepconfig at the start.
Obviously I don't want to go back into stepconfig again as everything will then be over written.

I only messed about with settings in the Z axis yesterday but now x and y are trying to home in the wrong direction. Z is aswell.

Also, if as you say, you touch off the Z axis at the top of axis and leave it alone after that,- then how do you set the cutter to the surface of whatever you're trying to cut before starting a project?

rodw wrote:

Here is how I have mine set up. Home is at the top and is 0.
bottom of travel is -65

So now jog to top of travel and touch off the Z axis at +65 using the GUI and never touch it again!

I have found this bit to be very confusing but the above fixes it.

Rod. This is not a plasma machine it is I think a small mill and uses a conventional Z axis the plasma PlasmaC code is done in python I believe so not relevant.

Jeff. Have you seen this: linuxcnc.org/docs/2.8/html/config/ini-homing.html

One of the problems when you was setting up was missing the H off in the z axis as that would cause linuxcnc not to read that line.

Homing is not difficult when you understand the way it works.

The direction it which the homing starts on each axis is determined by the sign ie -ve or +ve (you don't use +ve just the -)

in the home search velocity in the ini file Then the next bit which is the latch again use the sign to back off the switch.

You need to get the machine jogging correctly first on all axis ie page down Z comes down. etc.

You can use the SCALE sign to reverse a motor if it starts going the wrong way.

Edit: yes please attached you files as you have them now.

I would also add this to your ini file. As it will put the machine in a know state at startup.
[RS274NGC]
RS274NGC_STARTUP_CODE = G17 G21 G54 G40 G49 G64 G90
PARAMETER_FILE = linuxcnc.var

Hi everyone I really appreciate the help by the way. INI and Hal files below

# Generated by stepconf 1.1 at Sun Aug 30 18:04:07 2020
# If you make changes to this file, they will be
# overwritten when you run stepconf again
loadrt trivkins
loadrt [EMCMOT]EMCMOT base_period_nsec=[EMCMOT]BASE_PERIOD servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[TRAJ]AXES
loadrt hal_parport cfg="0 out"
setp parport.0.reset-time 1500
loadrt stepgen step_type=0,0,0
loadrt charge_pump
net estop-out charge-pump.enable iocontrol.0.user-enable-out
net charge-pump <= charge-pump.out

addf parport.0.read base-thread
addf stepgen.make-pulses base-thread
addf charge-pump base-thread
addf parport.0.write base-thread
addf parport.0.reset base-thread

addf stepgen.capture-position servo-thread
addf motion-command-handler servo-thread
addf motion-controller servo-thread
addf stepgen.update-freq servo-thread
net spindle-cmd-rpm <= motion.spindle-speed-out
net spindle-cmd-rpm-abs <= motion.spindle-speed-out-abs
net spindle-cmd-rps <= motion.spindle-speed-out-rps
net spindle-cmd-rps-abs <= motion.spindle-speed-out-rps-abs
net spindle-at-speed => motion.spindle-at-speed
net spindle-cw <= motion.spindle-forward

net estop-out => parport.0.pin-01-out
net xstep => parport.0.pin-02-out
setp parport.0.pin-02-out-reset 1
net xdir => parport.0.pin-03-out
net ystep => parport.0.pin-04-out
setp parport.0.pin-04-out-reset 1
net ydir => parport.0.pin-05-out
net zstep => parport.0.pin-06-out
setp parport.0.pin-06-out-reset 1
net zdir => parport.0.pin-07-out
net astep => parport.0.pin-08-out
setp parport.0.pin-08-out-reset 1
net adir => parport.0.pin-09-out
net spindle-cw => parport.0.pin-14-out
net charge-pump => parport.0.pin-16-out
net xenable => parport.0.pin-17-out
net all-home <= parport.0.pin-10-in

setp stepgen.0.position-scale [AXIS_0]SCALE
setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 29551
setp stepgen.0.dirsetup 29551
setp stepgen.0.maxaccel [AXIS_0]STEPGEN_MAXACCEL
net xpos-cmd axis.0.motor-pos-cmd => stepgen.0.position-cmd
net xpos-fb stepgen.0.position-fb => axis.0.motor-pos-fb
net xstep <= stepgen.0.step
net xdir <= stepgen.0.dir
net xenable axis.0.amp-enable-out => stepgen.0.enable
net all-home => axis.0.home-sw-in

setp stepgen.1.position-scale [AXIS_1]SCALE
setp stepgen.1.steplen 1
setp stepgen.1.stepspace 0
setp stepgen.1.dirhold 29551
setp stepgen.1.dirsetup 29551
setp stepgen.1.maxaccel [AXIS_1]STEPGEN_MAXACCEL
net ypos-cmd axis.1.motor-pos-cmd => stepgen.1.position-cmd
net ypos-fb stepgen.1.position-fb => axis.1.motor-pos-fb
net ystep <= stepgen.1.step
net ydir <= stepgen.1.dir
net yenable axis.1.amp-enable-out => stepgen.1.enable
net all-home => axis.1.home-sw-in

setp stepgen.2.position-scale [AXIS_2]SCALE
setp stepgen.2.steplen 1
setp stepgen.2.stepspace 0
setp stepgen.2.dirhold 29551
setp stepgen.2.dirsetup 29551
setp stepgen.2.maxaccel [AXIS_2]STEPGEN_MAXACCEL
net zpos-cmd axis.2.motor-pos-cmd => stepgen.2.position-cmd
net zpos-fb stepgen.2.position-fb => axis.2.motor-pos-fb
net zstep <= stepgen.2.step
net zdir <= stepgen.2.dir
net zenable axis.2.amp-enable-out => stepgen.2.enable
net all-home => axis.2.home-sw-in

net estop-out <= iocontrol.0.user-enable-out
net estop-out => iocontrol.0.emc-enable-in

loadusr -W hal_manualtoolchange
net tool-change iocontrol.0.tool-change => hal_manualtoolchange.change
net tool-changed iocontrol.0.tool-changed <= hal_manualtoolchange.changed
net tool-number iocontrol.0.tool-prep-number => hal_manualtoolchange.number
net tool-prepare-loopback iocontrol.0.tool-prepare => iocontrol.0.tool-prepared

# Generated by stepconf 1.1 at Sun Aug 30 18:04:07 2020
# If you make changes to this file, they will be
# overwritten when you run stepconf again

[EMC]
MACHINE = my-mill
DEBUG = 0

[DISPLAY]
DISPLAY = axis
EDITOR = gedit
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
ARCDIVISION = 64
GRIDS = 10mm 20mm 50mm 100mm 1in 2in 5in 10in
MAX_FEED_OVERRIDE = 1.2
MIN_SPINDLE_OVERRIDE = 0.5
MAX_SPINDLE_OVERRIDE = 1.2
DEFAULT_LINEAR_VELOCITY = 5.00
MIN_LINEAR_VELOCITY = 0
MAX_LINEAR_VELOCITY = 20.00
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 5
PROGRAM_PREFIX = /home/jeff65/linuxcnc/nc_files
INCREMENTS = 5mm 1mm .5mm .1mm .05mm .01mm .005mm

[FILTER]
PROGRAM_EXTENSION = .png,.gif,.jpg Greyscale Depth Image
PROGRAM_EXTENSION = .py Python Script
png = image-to-gcode
gif = image-to-gcode
jpg = image-to-gcode
py = python

[TASK]
TASK = milltask
CYCLE_TIME = 0.010

[RS274NGC]
PARAMETER_FILE = linuxcnc.var

[EMCMOT]
EMCMOT = motmod
COMM_TIMEOUT = 1.0
COMM_WAIT = 0.010
BASE_PERIOD = 37851
SERVO_PERIOD = 1000000

[HAL]
HALFILE = my-mill.hal
HALFILE = custom.hal
POSTGUI_HALFILE = custom_postgui.hal

[TRAJ]
AXES = 3
COORDINATES = X Y Z
LINEAR_UNITS = mm
ANGULAR_UNITS = degree
CYCLE_TIME = 0.010
DEFAULT_VELOCITY = 2.00
MAX_VELOCITY = 20.00

[EMCIO]
EMCIO = io
CYCLE_TIME = 0.100
TOOL_TABLE = tool.tbl

[AXIS_0]
TYPE = LINEAR
HOME = 5
MAX_VELOCITY = 12.5492060976
MAX_ACCELERATION = 13.0
STEPGEN_MAXACCEL = 16.25
SCALE = -2000.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = 0
MAX_LIMIT = 168
HOME_USE_INDEX = NO
HOME_OFFSET = 3
HOME_SEARCH_VEL = 1.000000
HOME_LATCH_VEL = 0.050000
HOME_FINAL_VEL = 2
HOME_SEQUENCE = 1

[AXIS_1]
TYPE = LINEAR
HOME = 5
MAX_VELOCITY = 12.5492060976
MAX_ACCELERATION = 13.0
STEPGEN_MAXACCEL = 16.25
SCALE = -2000.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = 0
MAX_LIMIT = 79
HOME_USE_INDEX = NO
HOME_OFFSET = 3
HOME_SEARCH_VEL = 1.000000
HOME_LATCH_VEL = 0.050000
HOME_FINAL_VEL = 2
HOME_SEQUENCE = 2

[AXIS_2]
TYPE = LINEAR
HOME = 0
MAX_VELOCITY = 12.5492060976
MAX_ACCELERATION = 13.0
STEPGEN_MAXACCEL = 16.25
SCALE = 2000.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = -75
MAX_LIMIT = 0.001
HOME_OFFSET = -64
HOME_SEARCH_VEL = 1.000000
HOME_LATCH_VEL = 0.050000
HOME_FINAL_VEL = 2
HOME_SEQUENCE = 0

Ok I see you have changed back some of the setting in the Z axis

[AXIS_2]
TYPE = LINEAR
HOME = 0
MAX_VELOCITY = 12.5492060976
MAX_ACCELERATION = 13.0
STEPGEN_MAXACCEL = 16.25
SCALE = 2000.0
FERROR = 1
MIN_FERROR = .25
MIN_LIMIT = -75
MAX_LIMIT = 0.001
HOME_OFFSET = -64
HOME_SEARCH_VEL = 1.000000
HOME_LATCH_VEL = 0.050000
HOME_FINAL_VEL = 2
HOME_SEQUENCE = 0

home_offset change it back to -2

Lets just concentrate on the z first. does it jog correctly before homing . ie page down z down

If you change anything please say what you have done otherwise we are in the dark.

At the moment the Z axis is moving the way it should - page up it goes up and page down it goes down and on the screen the same is apparent.

Its just when i try to home it goes off in the wrong direction

Jeff65 wrote:

At the moment the Z axis is moving the way it should - page up it goes up and page down it goes down and on the screen the same is apparent.

Its just when i try to home it goes off in the wrong direction

ok that's good. now change the sign on home_search vel ie put a - in front of the 2

did you change the home offset to -2