1. EMC2 and HAL
1.1. motion (realtime)
1.1.1. Options
1.1.2. Pins
1.1.3. Parameters
1.1.4. Functions
1.2. axis.N (realtime)
1.2.1. Pins
1.2.2. Parameters
1.3. iocontrol (userspace)
1.3.1. Pins

1 EMC2 and HAL

See also the manual pages motion(9) and iocontrol(1).

1.1 motion (realtime)

1.1.1 Options

Motion is loaded with the motmod command. A kins should be loaded before motion.

loadrt motmod [base_period_nsec=period] [servo_period_nsec=period] [traj_period_nsec=period] [num_joints=[0-9] ([num_dio=1-64] num_aio=1-16])]

If the number of digital I/O needed is above the default of 4 you can add up to 64 digital I/O by using the num_dio option when loading motmod.

If the number of analog I/O needed is more that the default of 4 you can add up to 16 analog I/O by using the num_aio option when loading motmod.

1.1.2 Pins

These pins, parameters, and functions are created by the realtime motmod module.

motion.adaptive-feed: (float, in) 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-00: (float, in) These pins (00, 01, 02, 03 or more if configured) are controlled by M66.
motion.analog-out-00: (float, out) These pins (00, 01, 02, 03 or more if configured) are controlled by M67 or M68.
motion.coord-error: (bit, out) TRUE when motion has encountered an error, such as exceeding a soft limit
motion.coord-mode: (bit, out) TRUE when motion is in "coordinated mode", as opposed to "teleop mode"
motion.current-vel: (float, out) The current tool velocity in user units per second.
motion.digital-in-00: (bit, in) These pins (00, 01, 02, 03 or more if configured) are controlled by M62-65.
motion.digital-out-00: (bit, out) These pins (00, 01, 02, 03 or more if configured) are controlled by the M62-65.
motion.distance-to-go: (float,out) The distance remaining in the current move.
motion.enable: (bit, in) 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: (bit, in) When Feed Stop Control is enabled with M53 P1, and this bit is TRUE, the feed rate is set to 0.
motion.in-position: (bit, out) TRUE if the machine is in position.
motion.motion-enabled: (bit, out) TRUE when in "machine on" state.
motion.on-soft-limit: (bit, out) TRUE when the machine is on a soft limit.
motion.probe-input: (bit, in) 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.program-line: (s32, out) The current program line while executing. Zero if not running or between lines while single stepping.
motion.requested-vel: (float, out) The current requested velocity in user units per second from the F=n setting in the G Code file. No feed overrides or any other adjustments are applied to this pin.
motion.spindle-at-speed: (bit, in) 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 to feed transition. This input can be used to ensure that the spindle is up to speed before starting a cut, or that a lathe spindle in CSS mode has slowed down after a large to small facing pass before starting the next pass at the large diameter. Many VFDs have an "at speed" output. Otherwise, it is easy to generate this signal with the HAL near component, by comparing requested and actual spindle speeds.
motion.spindle-brake: (bit, out) TRUE when the spindle brake should be applied.
motion.spindle-forward: (bit, out) TRUE when the spindle should rotate forward.
motion.spindle-index-enable: (bit, I/O) For correct operation of spindle synchronized moves, this pin must be hooked to the index-enable pin of the spindle encoder.
motion.spindle-on: (bit, out) TRUE when spindle should rotate.
motion.spindle-reverse: (bit, out) TRUE when the spindle should rotate backward
motion.spindle-revs: (float, in) For correct operation of spindle synchronized moves, this signal must be hooked to the position pin of the spindle encoder. The spindle encoder position should be scaled such that spindle-revs increases by 1.0 for each rotation of the spindle in the clockwise (M3) direction.
motion.spindle-speed-in: (float, in) Feedback of actual spindle speed in rotations per second. This is used by feed-per-revolution motion (G95). If your spindle encoder driver does not have a velocity output, you can generate a suitable one by sending the spindle position through a ddt component.
motion.spindle-speed-out: (float, out) Commanded spindle speed in rotations per minute. Positive for spindle forward (M3), negative for spindle reverse (M4).
motion.spindle-speed-out-rps: (float, out) Commanded spindle speed in rotations per second. Positive for spindle forward (M3), negative for spindle reverse (M4).
motion.teleop-mode: (bit, out) TRUE when motion is in "teleop mode", as opposed to "coordinated mode"
motion.tooloffset.w: (float, out) shows the w offset in effect; it could come from the tool table (G43 active), or it could come from the gcode (G43.1 active)
motion.tooloffset.x: (float, out) shows the x offset in effect; it could come from the tool table (G43 active), or it could come from the gcode (G43.1 active)
motion.tooloffset.z: (float, out) shows the z offset in effect; it could come from the tool table (G43 active), or it could come from the gcode (G43.1 active)

1.1.3 Parameters

Many of these parameters serve as debugging aids, and are subject to change or removal at any time.

motion-command-handler.time: (s32, RO)
motion-command-handler.tmax: (s32, RW)
motion-controller.time: (s32, RO)
motion-controller.tmax: (s32, RW)
motion.debug-bit-0: (bit, RO) This is used for debugging purposes.
motion.debug-bit-1: (bit, RO) This is used for debugging purposes.
motion.debug-float-0: (float, RO) This is used for debugging purposes.
motion.debug-float-1: (float, RO) This is used for debugging purposes.
motion.debug-float-2: (float, RO) This is used for debugging purposes.
motion.debug-float-3: (float, RO) This is used for debugging purposes.
motion.debug-s32-0: (s32, RO) This is used for debugging purposes.
motion.debug-s32-1: (s32, RO) This is used for debugging purposes.
motion.servo.last-period: (u32, RO) 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
motion.servo.last-period-ns: (float, RO)
motion.servo.overruns: (u32, RW) 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.

1.1.4 Functions

Generally, these functions are both added to the servo-thread in the order shown.

motion-command-handler: Processes motion commands coming from user space
motion-controller: Runs the EMC motion controller

1.2 axis.N (realtime)

These pins and parameters are created by the realtime motmod module. These are actually joint values, but the pins and parameters are still called "axis.N".¹ They are read and updated by the motion-controller function.

1.2.1 Pins

axis.N.active: (bit, out)
axis.N.amp-enable-out: (bit, out) TRUE if the amplifier for this joint should be enabled
axis.N.amp-fault-in: (bit, in) Should be driven TRUE if an external fault is detected with the amplifier for this joint
axis.N.backlash-corr: (float, out)
axis.N.backlash-filt: (float, out)
axis.N.backlash-vel: (float, out)
axis.N.coarse-pos-cmd: (float, out)
axis.N.error: (bit, out)
axis.N.f-error: (float, out)
axis.N.f-error-lim: (float, out)
axis.N.f-errored: (bit, out)
axis.N.faulted: (bit, out)
axis.N.free-pos-cmd: (float, out)
axis.N.free-tp-enable: (bit, out)
axis.N.free-vel-lim: (float, out)
axis.N.home-sw-in: (bit, in) Should be driven TRUE if the home switch for this joint is closed.
axis.N.homed: (bit, out)
axis.N.homing: (bit, out) TRUE if the joint is currently homing
axis.N.in-position: (bit, out)
axis.N.index-enable: (bit, I/O)
axis.N.jog-counts: (s32, in) Connect to the "counts" pin of an external encoder to use a physical jog wheel.
axis.N.jog-enable: (bit, in) When TRUE (and in manual mode), any change in "jog-counts" will result in motion. When false, "jog-counts" is ignored.
axis.N.jog-scale: (float, in) Sets the distance moved for each count on "jog-counts", in machine units.
axis.N.jog-vel-mode: (bit, in) 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: (float, out) The joint (as opposed to motor) commanded position. There may be an offset between the joint and motor positions--for example, the homing process sets this offset.
axis.N.joint-pos-fb: (float, out) The joint (as opposed to motor) feedback position.
axis.N.joint-vel-cmd: (float, out)
axis.N.kb-jog-active: (bit, out)
axis.N.motor-pos-cmd: (float, out) The commanded position for this joint.
axis.N.motor-pos-fb: (float, in) The actual position for this joint.
axis.N.neg-hard-limit: (bit, out)
axis.N.pos-lim-sw-in: (bit, in) Should be driven TRUE if the positive limit switch for this joint is closed
axis.N.pos-hard-limit: (bit, out)
axis.N.neg-lim-sw-in: (bit, in) Should be driven TRUE if the negative limit switch for this joint is closed
axis.N.wheel-jog-active: (bit, out)

1.2.2 Parameters

axis.N.home-state: Reflects the step of homing currently taking place

1.3 iocontrol (userspace)

These pins are created by the userspace IO controller, usually called io.

1.3.1 Pins

iocontrol.0.coolant-flood: (bit, out) TRUE when flood coolant is requested
iocontrol.0.coolant-mist: (bit, out) TRUE when mist coolant is requested
iocontrol.0.emc-enable-in: (bit, in) Should be driven FALSE when an external E-Stop condition exists
iocontrol.0.lube: (bit, out) TRUE when lube is commanded
iocontrol.0.lube_level: (bit, in) Should be driven TRUE when lube level is high enough
iocontrol.0.tool-change: (bit, out) TRUE when a tool change is requested
iocontrol.0.tool-changed: (bit, in) Should be driven TRUE when a tool change is completed
iocontrol.0.tool-number: (s32, out) The current tool number
iocontrol.0.tool-prep-number: (s32, out) The number of the next tool, from the RS274NGC T-word
iocontrol.0.tool-prepare: (bit, out) TRUE when a tool prepare is requested
iocontrol.0.tool-prepared: (bit, in) Should be driven TRUE when a tool prepare is completed
iocontrol.0.user-enable-out: (bit, out) FALSE when an internal E-Stop condition exists
iocontrol.0.user-request-enable: (bit, out) TRUE when the user has requested that E-Stop be cleared

Footnotes

1 In "trivial kinematics" machines, there is a one-to-one correspondence between joints and axes. back

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