motion − accepts NML motion commands, interacts with HAL in realtime
loadrt motmod [base_period_nsec=period] [base_thread_fp=0 or 1] [servo_period_nsec=period] [traj_period_nsec=period] [num_joints=[0-9]] ([num_dio=[1-64]] [num_aio=[1-16]])
By default, the base thread does not support floating point. Software stepping, software encoder counting, and software pwm do not use floating point. base_thread_fp can be used to enable floating point in the base thread (for example for brushless DC motor control).
These pins and parameters are created by the realtime motmod module. This module provides a HAL interface for LinuxCNC’s motion planner. Basically motmod takes in a list of waypoints and generates a nice blended and constraint-limited stream of joint positions to be fed to the motor drives.
Optionally the number of Digital I/O is set with num_dio. The number of Analog I/O is set with num_aio. The default is 4 each.
Pin names starting with "axis" are actually joint values, but the pins and parameters are still called "axis.N". They are read and updated by the motion-controller function.
axis.N.amp-enable-out OUT BIT
TRUE if the amplifier for this joint should be enabled
axis.N.amp-fault-in IN BIT
Should be driven TRUE if an external fault is detected with the amplifier for this joint
axis.N.home-sw-in IN BIT
Should be driven TRUE if the home switch for this joint is closed
axis.N.homing OUT BIT
TRUE if the joint is currently homing
axis.N.index-enable IO BIT
Should be attached to the index-enable pin of the joint’s encoder to enable homing to index pulse
axis.N.is-unlocked IN BIT
If the axis is a locked rotary the unlocked sensor should be connected to this pin
axis.N.jog-counts IN S32
Connect to the "counts" pin of an external encoder to use a physical jog wheel.
axis.N.jog-enable IN BIT
When TRUE (and in manual mode), any change to "jog-counts" will result in motion. When false, "jog-counts" is ignored.
axis.N.jog-scale IN FLOAT
Sets the distance moved for each count on "jog-counts", in machine units.
axis.N.jog-vel-mode IN BIT
When FALSE (the default), the jogwheel operates in position mode. The axis will move exactly jog-scale units for each count, regardless of how long that might take. When TRUE, the wheel operates in velocity mode - motion stops when the wheel stops, even if that means the commanded motion is not completed.
axis.N.joint-pos-cmd OUT FLOAT
The joint (as opposed to motor) commanded position. There may be several offsets between the joint and motor coordinates: backlash compensation, screw error compensation, and home offsets.
axis.N.joint-pos-fb OUT FLOAT
The joint feedback position. This value is computed from the actual motor position minus joint offsets. Useful for machine visualization.
axis.N.motor-pos-cmd OUT FLOAT
The commanded position for this joint.
axis.N.motor-pos-fb IN FLOAT
The actual position for this joint.
axis.N.neg-lim-sw-in IN BIT
Should be driven TRUE if the negative limit switch for this joint is tripped.
axis.N.pos-lim-sw-in IN BIT
Should be driven TRUE if the positive limit switch for this joint is tripped.
axis.N.unlock OUT BIT
TRUE if the axis is a locked rotary and a move is commanded.
motion.adaptive-feed IN FLOAT
When adaptive feed is enabled with M52 P1, the commanded velocity is multiplied by this value. This effect is multiplicative with the NML-level feed override value and motion.feed-hold.
motion.analog-in-NN IN FLOAT
These pins are used by M66 Enn wait-for-input mode.
motion.analog-out-NN OUT FLOAT
These pins are used by M67-68.
motion.coord-error OUT BIT
TRUE when motion has encountered an error, such as exceeding a soft limit
motion.coord-mode OUT BIT
TRUE when motion is in "coordinated mode", as opposed to "teleop mode"
motion.current-vel OUT FLOAT
Current cartesian velocity
motion.digital-in-NN IN BIT
These pins are used by M66 Pnn wait-for-input mode.
motion.digital-out-NN OUT BIT
These pins are controlled by the M62 through M65 words.
motion.distance-to-go OUT FLOAT
Distance remaining in the current move
motion.enable IN BIT
If this bit is driven FALSE, motion stops, the machine is placed in the "machine off" state, and a message is displayed for the operator. For normal motion, drive this bit TRUE.
motion.feed-hold IN BIT
When Feed Stop Control is enabled with M53 P1, and this bit is TRUE, the feed rate is set to 0.
motion.motion-inpos OUT BIT
TRUE if the machine is in position.
motion.probe-input IN BIT
G38.x uses the value on this pin to determine when the probe has made contact. TRUE for probe contact closed (touching), FALSE for probe contact open.
motion.requested-vel OUT FLOAT
The requested velocity with no adjustments for feed override
motion.spindle-at-speed IN BIT
Motion will pause until this pin is TRUE, under the following conditions: before the first feed move after each spindle start or speed change; before the start of every chain of spindle-synchronized moves; and if in CSS mode, at every rapid->feed transition.
motion.spindle-brake OUT BIT
TRUE when the spindle brake should be applied
motion.spindle-forward OUT BIT
TRUE when the spindle should rotate forward
motion.spindle-index-enable I/O BIT
For correct operation of spindle synchronized moves, this signal must be hooked to the index-enable pin of the spindle encoder.
motion.spindle-on OUT BIT
TRUE when spindle should rotate
motion.spindle-reverse OUT BIT
TRUE when the spindle should rotate backward
motion.spindle-revs IN FLOAT
For correct operation of spindle synchronized moves, this signal must be hooked to the position pin of the spindle encoder.
motion.spindle-speed-in IN FLOAT
Actual spindle speed feedback in revolutions per second; used for G96 feed-per-revolution and constant surface speed modes.
motion.spindle-speed-out OUT FLOAT
Desired spindle speed in rotations per minute
motion.spindle-speed-out-rps OUT float
Desired spindle speed in rotations per second
motion.tooloffset.y OUT FLOAT
motion.tooloffset.z OUT FLOAT
motion.tooloffset.a OUT FLOAT
motion.tooloffset.b OUT FLOAT
motion.tooloffset.c OUT FLOAT
motion.tooloffset.u OUT FLOAT
motion.tooloffset.v OUT FLOAT
motion.tooloffset.w OUT FLOAT
Current tool offset in all 9 axes.
Many of the
pins below serve as debugging aids, and are subject to
change or removal at any time.
axis.N.active OUT BIT
TRUE when this joint is active
axis.N.backlash-corr OUT FLOAT
Backlash or screw compensation raw value
axis.N.backlash-filt OUT FLOAT
Backlash or screw compensation filtered value (respecting motion limits)
axis.N.backlash-vel OUT FLOAT
Backlash or screw compensation velocity
axis.N.error OUT BIT
TRUE when this joint has encountered an error, such as a limit switch closing
axis.N.f-error OUT FLOAT
The actual following error
axis.N.f-error-lim OUT FLOAT
The following error limit
axis.N.f-errored OUT BIT
TRUE when this joint has exceeded the following error limit
axis.N.free-pos-cmd OUT FLOAT
The "free planner" commanded position for this joint.
axis.N.free-tp-enable OUT BIT
TRUE when the "free planner" is enabled for this joint
axis.N.free-vel-lim OUT FLOAT
The velocity limit for the free planner
axis.N.homed OUT BIT
TRUE if the joint has been homed
axis.N.in-position OUT BIT
TRUE if the joint is using the "free planner" and has come to a stop
axis.N.joint-vel-cmd OUT FLOAT
The joint’s commanded velocity
axis.N.neg-hard-limit OUT BIT
The negative hard limit for the joint
axis.N.pos-hard-limit OUT BIT
The positive hard limit for the joint
motion.in-position OUT BIT
Same as the pin motion.motion-inpos
motion.on-soft-limit OUT BIT
motion.program-line OUT S32
motion.teleop-mode OUT BIT
TRUE when motion is in "teleop mode", as opposed to "coordinated mode"
Many of the
parameters serve as debugging aids, and are subject to
change or removal at any time.
Show information about the execution time of these HAL functions in CPU cycles
These values are used for debugging purposes.
The number of CPU cycles between invocations of the servo thread. Typically, this number divided by the CPU speed gives the time in seconds, and can be used to determine whether the realtime motion controller is meeting its timing constraints
By noting large differences between successive values of motion.servo.last-period, the motion controller can determine that there has probably been a failure to meet its timing constraints. Each time such a failure is detected, this value is incremented.
these functions are both added to the servo-thread in the
Processes motion commands coming from user space
Runs the LinuxCNC motion controller
This manual page is horribly incomplete.