1 EMC2 and HAL

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

1.1 motion (realtime)

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

1.1.1 Pins

motion.adaptive-feed IN float: When adaptive feed is enabled with M52 P1 (See the G Code Manual), the commanded velocity is multiplied by this value. This effect is multiplicative with the NML-level feed override value and motion.feed-hold.
motion.digital-out-NN OUT bit: These pins are controlled by the M62 through M65 words.
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 (See the G Code Manual), 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: G38.2 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.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-reverse OUT bit: TRUE when the spindle should rotate backward
motion.spindle-on OUT bit: TRUE when spindle should rotate
motion.spindle-speed-out OUT float: Desired spindle speed in rotations per minute
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-revs IN float: For correct operation of spindle synchronized moves, this signal must be hooked to the position pin of the spindle encoder.

1.1.2 Parameters

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

motion.coord-error: TRUE when motion has encountered an error, such as exceeding a soft limit
motion.coord-mode: TRUE when motion is in “coordinated mode”, as opposed to “teleop mode”
motion.in-position: Same as the pin motion.motion-inpos
motion.motion-enabled: TRUE when motion is enabled
motion.servo.last-period: 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 real time motion controller is meeting its timing constraints
motion.servo.overruns: 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.
motion.debug-bit-0
motion.debug-bit-1
motion.debug-float-0
motion.debug-float-1: These values are used for debugging purposes.

1.1.3 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 real time 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.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.pos-lim-sw-in IN bit: Should be driven TRUE if the positive limit switch for this joint is closed
axis.N.neg-lim-sw-in IN bit: Should be driven TRUE if the negative limit switch for this joint is closed
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.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 in “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 jog wheel 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.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.joint-pos-cmd: 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: The joint (as opposed to motor) feedback position.

1.2.2 Parameters

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

axis.N.active: TRUE when this joint is active
axis.N.backlash-corr: Backlash or screw compensation raw value
axis.N.backlash-filt: Backlash or screw compensation filtered value (respecting motion limits)
axis.N.backlash-vel: Backlash or screw compensation velocity
axis.N.coarse-pos-cmd
axis.N.error: TRUE when this joint has encountered an error, such as a limit switch closing
axis.N.f-error: The actual following error
axis.N.f-error-lim: The following error limit
axis.N.f-errored: TRUE when this joint has exceeded the following error limit
axis.N.free-pos-cmd: The “free planner” commanded position for this joint.
axis.N.free-tp-enable: TRUE when the “free planner” is enabled for this joint
axis.N.free-vel-lim: The velocity limit for the free planner
axis.N.home-state: Reflects the step of homing currently taking place
axis.N.homed: TRUE if the joint has been homed
axis.N.in-position: TRUE if the joint is using the “free planner” and has come to a stop
axis.N.joint-vel-cmd: The joint's commanded velocity
axis.N.neg-hard-limit: The negative hard limit for the joint
axis.N.neg-soft-limit: The negative soft limit for the joint
axis.N.pos-hard-limit: The positive hard limit for the joint
axis.N.pos-soft-limit: The positive soft limit for the joint

1.3 iocontrol (userspace)

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

1.3.1 Pins

iocontrol.0.coolant-flood: TRUE when flood coolant is requested
iocontrol.0.coolant-mist: TRUE when mist coolant is requested
iocontrol.0.emc-enable-in: Should be driven FALSE when an external e-stop condition exists
iocontrol.0.lube
iocontrol.0.lube_level: Should be driven TRUE when
iocontrol.0.tool-change: TRUE when a tool change is requested
iocontrol.0.tool-changed: Should be driven TRUE when a tool change is completed
iocontrol.0.tool-prep-number: The number of the next tool, from the RS274NGC T-word
iocontrol.0.tool-prepare: TRUE when a tool prepare is requested
iocontrol.0.tool-prepared: Should be driven TRUE when a tool prepare is completed
iocontrol.0.user-enable-out: FALSE when an internal e-stop condition exists
iocontrol.0.user-request-enable: 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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