CNC Router - Dual Y's / Gantry

As said, please attach your ini file. That is what controlls the behaviour

In my experience whenever homing is not working as described in the docs, its always a wiring fault. Motor plugged to wrong driver, or wrong home switch used on a joint. SO easy to do and it becomes very confusing.

Here is my .ini file

[EMC]
MACHINE = PrintNC
DEBUG = 0
VERSION = 1.1

[DISPLAY]
DISPLAY = gmoccapy
PREFERENCE_FILE_PATH = gmoccapy.preferences
EDITOR = gedit
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
ARCDIVISION = 64
GRIDS = 10mm 20mm 50mm 100mm 1in 2in 5in 10in
MAX_FEED_OVERRIDE = 1.5
MIN_SPINDLE_OVERRIDE = 1.2
MAX_SPINDLE_OVERRIDE = 3

#COPIED THE NEXT LINES FOR VELOCITY TO THE TRAJ SECTION
#AXIS USES THESE HERE, GMOCCAPY USES THEM IN TRAJ
DEFAULT_LINEAR_VELOCITY = 75.00
# Set Min mm/sec of JOG speed
MIN_LINEAR_VELOCITY = 0
# Set Max mm/sec of JOG speed
MAX_LINEAR_VELOCITY = 100.00

INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 2
PROGRAM_PREFIX = /home/jeff/linuxcnc/nc_files
INCREMENTS = 5mm 1mm .5mm .1mm .05mm .01mm .005mm
PYVCP = custompanel.xml

[KINS]
JOINTS = 4
#Joints is changed from 3 to 4. This will define the second motor that is used for the Y axis.
KINEMATICS = trivkins coordinates=XYYZ
#Kinematics is changed from XYZ to XYYZ. This will define the second motor that is used for the Y axis.

[FILTER]
PROGRAM_EXTENSION = .png,.gif,.jpg Greyscale Depth Image
PROGRAM_EXTENSION = .py Python Script
PROGRAM_EXTENSION = .nc,.tap G-Code File
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
BASE_PERIOD = 50000
SERVO_PERIOD = 1000000

[HAL]
HALFILE = PrintNC.hal
HALFILE = custom.hal
HALFILE = vfd.hal
POSTGUI_HALFILE = custom_postgui.hal
POSTGUI_HALFILE = postgui_call_list.hal

[TRAJ]
COORDINATES = XYYZ
#Coordinates is changed from XYZ to XYYZ. This will define the second motor that is used for the Y axis.
LINEAR_UNITS = mm
ANGULAR_UNITS = degree
#Next settings are here for jog speeds and slider display on gmoccappy
#Jog Speed here mm/sec
DEFAULT_LINEAR_VELOCITY = 100.00
#Slider Minimum Range mm/sec
MIN_LINEAR_VELOCITY = 0
#Slider Maximum Range mm/sec
MAX_LINEAR_VELOCITY = 100.00

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

[AXIS_X]
MAX_VELOCITY = 80.00
MAX_ACCELERATION = 300.0
MIN_LIMIT = -1146.0
MAX_LIMIT = 1.0

[JOINT_0]
TYPE = LINEAR
HOME = 0.0
MIN_LIMIT = -1146.0
MAX_LIMIT 1.0
MAX_VELOCITY = 100.00
MAX_ACCELERATION = 320.0
STEPGEN_MAXACCEL = 320.0
SCALE = 80.0
FERROR = 10
MIN_FERROR = 1.0
HOME_OFFSET = 5.0
#Manual Homing Section
HOME_SEARCH_VEL = -35
HOME_LATCH_VEL = 5
HOME_FINAL_VEL = 20
HOME_SEQUENCE = 1


[AXIS_Y]
MAX_VELOCITY = 80.00
MAX_ACCELERATION = 300
MIN_LIMIT = -868
MAX_LIMIT = 1

[JOINT_1]
TYPE = LINEAR
HOME = 0
MIN_LIMIT = -868.0
MAX_LIMIT = 1.0
MAX_VELOCITY = 100.0
MAX_ACCELERATION = 320.00
STEPGEN_MAXACCEL = 320.00
SCALE = -80.0
FERROR = 3
MIN_FERROR = 1
HOME_OFFSET = 5.0
HOME_SEARCH_VEL = -35
HOME_LATCH_VEL = 5
HOME_FINAL_VEL = 20
HOME_SEQUENCE = -1

[JOINT_2]
TYPE = LINEAR
HOME = 0
MIN_LIMIT = -868.0
MAX_LIMIT = 1.0
MAX_VELOCITY = 100.00
MAX_ACCELERATION = 320.00
STEPGEN_MAXACCEL = 320.00
SCALE = -80.0
FERROR = 3
MIN_FERROR = 1
HOME_OFFSET = 5.0
HOME_SEARCH_VEL = -35
HOME_LATCH_VEL = 5
HOME_FINAL_VEL = 20
HOME_SEQUENCE = -1

#HOME_SEARCH_VEL = 0
#HOME_LATCH_VEL = 0
#HOME_USE_INDEX = NO
#HOME_SEQUENCE = -1

[AXIS_Z]
MAX_VELOCITY = 40.0
MAX_ACCELERATION = 500
MIN_LIMIT = -120
MAX_LIMIT = 1.0

[JOINT_3]
TYPE = LINEAR
HOME = 0
MIN_LIMIT = -120
MAX_LIMIT = 1.0
MAX_VELOCITY = 50.0
MAX_ACCELERATION = 520.0
STEPGEN_MAXACCEL = 520.0
SCALE = 200
FERROR = 1
MIN_FERROR = 0.25
HOME_OFFSET = 5
HOME_SEARCH_VEL = -35
HOME_LATCH_VEL = -5
HOME_FINAL_VEL = 20
HOME_SEQUENCE = 0

#HOME_SEARCH_VEL = 0
#HOME_LATCH_VEL = 0
#HOME_USE_INDEX = NO
#HOME_SEQUENCE = 0

Just to clarify, jogging the machine and then homing doesn't return any errors. I can run the machine (jog) at all speeds, any directions, for any length of time I want. And homing returns both switches being depressed at the same time. I'm only having a problem with running gcode.

Hole patterns are skewed slightly, but that slightly grows over movement.

And when I home after the job, is when I see that the x gantry hits the switches at different times.

By the way, thank you for sticking with me on this.

When I look at your ini file, the joint axis with 2 motors is the Y axis. Thats how mine is set up. You keep saying X.
The Ini file looks OK

From here, I would use halshow and get it to show all parallel port homing pins. Go around the machine and manually trigger every pin and watch to make sure they are as you expect them to be

I would then repeat the exercise monitoring and be sure these are all as expected
If that does not work, I would slow down the search velocities to a crawl and watch what happens on those pins and the machine.

The switches have been tested multiple times using the Hal monitor. They seem to be working with no issues.

My question at this point is this. Are there different .ini settings which control jogging vs running gcode during a job on the machine?

It makes no sense to me that I can jog and jog and jog, hit the home button and have perfect alignment on the two rear Y switches. But when I run a job with gcode, I end up with a mis-aligned Gantry to the switches after.

How is that possible?

Jogging is nowhere near as hard on the forces as real gcode is. I found out that the hard way when set my max acceleration and velocities. After running some code, I had to back off. If you have anything sticking it will find it.

I believe I've found the problem!

I've compared .ini files so many times, I felt certain the foundation was correct. But I missed a parameter which was missing completely

Axes in the Traj section

I added that line in the TRAJ section... with axes = 3 and have run multiple jobs with no issues

Thank you all for pushing me to keep looking