After a few more hours head scratching I figured out most of what is
going on. In some cases LinuxCNC is calculating the work envelope
incorrectly. The axis limit warnings are based on the work envelope.
From my testing it looks like it is sometimes messing up the tool
offsets when it does a simulation run.
I can now replicate this bug using a sim configuration. Create a
sim.axis, axis_mm configuration and drop in the attached ini file (only
the Z axis extents and home position are changed from standard).
Start Axis and home it. In MDI:
M6 T1
G43 H1
Jog down to the Z minimum limit then jog up a bit (say 10mm or so). Tool
touch off Z and set it to 0. Load the attached ngc file and run it. The
file will run correctly. Turn on View->show extents. Pay attention to
the Z axis size. It should be around 80 - 90mm.
In MDI:
M6T1
Now reload the program and run. You should get a warning 'Program
exceeds machine maximum on axis Z'. If you click 'Run anyway' it will
run correctly. Look at the work extents. Z is now around 170- 180.
Restart Axis, home and load the program. It will run correctly. In MDI:
M6T1
Reload the program. Now you get the error.
This configuration is specifically set up to show the error as clearly
as possible. However you can probably see it in most configurations. Set
up a fairly long tool offset and use code similar to my ngc file. The
important parts are the G43 followed by one or more G1 moves, including
the Z axis. Load the file and look at the Z extent. Now in MDI
M6Tx (use whatever tool number is relevant)
Reload the file and you will see the Z extents have changed.
Les
G90 G40 G21
M6 T1
G43H1
G1 X100 Y100 f2000
G1 Z0
M30
# EMC controller parameters for a simulated machine.
# General note: Comments can either be preceded with a # or ; - either is
# acceptable, although # is in keeping with most linux config files.
# General section -------------------------------------------------------------
[EMC]
# Version of this INI file
VERSION = 1.0
# Name of machine, for use with display, etc.
MACHINE = LinuxCNC-HAL-SIM-AXIS
# Debug level, 0 means no messages. See src/emc/nml_int/emcglb.h for others
# DEBUG = 0x7FFFFFFF
DEBUG = 0
# Sections for display options ------------------------------------------------
[DISPLAY]
# Name of display program, e.g., axis
DISPLAY = axis
# Cycle time, in seconds, that display will sleep between polls
CYCLE_TIME = 0.100
# Path to help file
HELP_FILE = doc/help.txt
# Initial display setting for position, RELATIVE or MACHINE
POSITION_OFFSET = RELATIVE
# Initial display setting for position, COMMANDED or ACTUAL
POSITION_FEEDBACK = ACTUAL
# Highest value that will be allowed for feed override, 1.0 = 100%
MAX_FEED_OVERRIDE = 1.2
MAX_SPINDLE_OVERRIDE = 1.0
# Prefix to be used
PROGRAM_PREFIX = /home/lathe/linuxcnc/nc_files
# Introductory graphic
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 5
EDITOR = gedit
INCREMENTS = 1 mm, .01 in, .1mm, 1 mil, .1 mil, 1/8000 in
[FILTER]
PROGRAM_EXTENSION = .png,.gif,.jpg Grayscale Depth Image
PROGRAM_EXTENSION = .py Python Script
png = image-to-gcode
gif = image-to-gcode
jpg = image-to-gcode
py = python
# Task controller section -----------------------------------------------------
[TASK]
# Name of task controller program, e.g., milltask
TASK = milltask
# Cycle time, in seconds, that task controller will sleep between polls
CYCLE_TIME = 0.001
# Part program interpreter section --------------------------------------------
[RS274NGC]
# File containing interpreter variables
PARAMETER_FILE = sim_mm.var
# Motion control section ------------------------------------------------------
[EMCMOT]
EMCMOT = motmod
# Timeout for comm to emcmot, in seconds
COMM_TIMEOUT = 1.0
# BASE_PERIOD is unused in this configuration but specified in core_sim.hal
BASE_PERIOD = 0
# Servo task period, in nano-seconds
SERVO_PERIOD = 1000000
# section for main IO controller parameters -----------------------------------
[EMCIO]
# Name of IO controller program, e.g., io
EMCIO = io
# cycle time, in seconds
CYCLE_TIME = 0.100
# tool table file
TOOL_TABLE = sim_mm.tbl
TOOL_CHANGE_POSITION = 0 0 0
# Hardware Abstraction Layer section
--------------------------------------------------
[HAL]
# The run script first uses halcmd to execute any HALFILE
# files, and then to execute any individual HALCMD commands.
#
# list of hal config files to run through halcmd
# files are executed in the order in which they appear
HALFILE = core_sim.hal
HALFILE = sim_spindle_encoder.hal
HALFILE = axis_manualtoolchange.hal
HALFILE = simulated_home.hal
# list of halcmd commands to execute
# commands are executed in the order in which they appear
#HALCMD = save neta
# Single file that is executed after the GUI has started. Only supported by
# AXIS at this time (only AXIS creates a HAL component of its own)
#POSTGUI_HALFILE = test_postgui.hal
HALUI = halui
# Trajectory planner section --------------------------------------------------
[TRAJ]
COORDINATES = X Y Z
LINEAR_UNITS = mm
ANGULAR_UNITS = degree
DEFAULT_LINEAR_VELOCITY = 30.48
MAX_LINEAR_VELOCITY = 53.34
DEFAULT_LINEAR_ACCEL = 508
MAX_LINEAR_ACCEL = 508
POSITION_FILE = position_mm.txt
[KINS]
KINEMATICS = trivkins
JOINTS = 3
# Axes sections ---------------
[AXIS_X]
MAX_VELOCITY = 30.48
MAX_ACCELERATION = 508
MIN_LIMIT = -254
MAX_LIMIT = 254
[AXIS_Y]
MAX_VELOCITY = 30.48
MAX_ACCELERATION = 508
MIN_LIMIT = -254
MAX_LIMIT = 254
[AXIS_Z]
MAX_VELOCITY = 30.48
MAX_ACCELERATION = 508
MIN_LIMIT = -101
MAX_LIMIT = 1
# Joints sections -------------
[JOINT_0]
TYPE = LINEAR
HOME = 0.000
MAX_VELOCITY = 30.48
MAX_ACCELERATION = 508
BACKLASH = 0.000
INPUT_SCALE = 157.48
OUTPUT_SCALE = 1.000
MIN_LIMIT = -254
MAX_LIMIT = 254
FERROR = 1.27
MIN_FERROR = .254
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = 127
HOME_LATCH_VEL = 25.4
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO
HOME_SEQUENCE = 1
HOME_IS_SHARED = 1
[JOINT_1]
TYPE = LINEAR
HOME = 0.000
MAX_VELOCITY = 30.48
MAX_ACCELERATION = 508
BACKLASH = 0.000
INPUT_SCALE = 157.48
OUTPUT_SCALE = 1.000
MIN_LIMIT = -254
MAX_LIMIT = 254
FERROR = 1.27
MIN_FERROR = .254
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = 127
HOME_LATCH_VEL = 25.4
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO
HOME_SEQUENCE = 1
[JOINT_2]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 30.48
MAX_ACCELERATION = 508
BACKLASH = 0.000
INPUT_SCALE = 157.48
OUTPUT_SCALE = 1.000
MIN_LIMIT = -101.5
MAX_LIMIT = 1.5
FERROR = 1.27
MIN_FERROR = .254
HOME_OFFSET = 25.4
HOME_SEARCH_VEL = 127
HOME_LATCH_VEL = 25.4
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO
HOME_SEQUENCE = 0
HOME_IS_SHARED = 1
------------------------------------------------------------------------------
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