path: root/docs/src/config/emc2hal.txt

= Core Components

[[cha:core-components]] (((Core Components)))

See also the man pages 'motion(9)'.

[[sec:motion]]
== Motion

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.

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])] 
----

* 'base_period_nsec = 50000' - the 'Base' task period in nanoseconds.
  This is the fastest thread in the machine.

[NOTE]
On servo-based systems, there is generally no reason for
'base_period_nsec' to be smaller than 'servo_period_nsec'.
On machines with software step generation, the 'base_period_nsec'
determines the maximum number of steps per second. In the absence of
long step length and step space requirements, the absolute maximum step
rate is one step per 'base_period_nsec'. Thus, the 'base_period_nsec' shown
above gives an absolute maximum step rate of 20,000 steps per
second. 50,000 ns (50 us) is a fairly conservative value. The
smallest usable value is related to the Latency Test result, the
necessary step length, and the processor speed.
Choosing a 'base_period_nsec' that is too low can lead to the "Unexpected
real time delay" message, lockups, or spontaneous reboots.

* 'servo_period_nsec = 1000000' - This is the 'Servo' task period in
  nanoseconds. This value will be rounded to an integer multiple of
  'base_period_nsec'. This period is used even on systems based on
  stepper motors.
+
This is the rate at which new motor positions are computed, following
error is checked, PID output values are updated, and so on.
Most systems will not need to change this value. It is the update rate
of the low level motion planner.

* 'traj_period_nsec = 100000' - This is the 'Trajectory Planner'
  task period in nanoseconds. This value will be rounded to an integer
  multiple of 'servo_period_nsec'. Except for machines with unusual 
  kinematics (e.g., hexapods) there is no reason to make this value larger
  than 'servo_period_nsec'.


=== Options

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

=== Pins (((motion (HAL 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.feed-inhibit' - 
     (bit, in) When this bit is TRUE, the feed rate is set to 0.
    This will be delayed during spindle synch moves till the end of the move.

* '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-inhibit' - 
     (bit, in) When this bit is TRUE, the spindle speed is set to 0.

* '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.  If you do not have a spindle encoder, you can loop 
    back 'motion.spindle-speed-out-rps'.

* '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-abs' - 
     (float, out) Commanded spindle speed in rotations per minute. This will
    always be a positive number.

* '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.spindle-speed-out-rps-abs' - 
     (float, out) Commanded spindle speed in rotations per second. This will
    always be a positive number.

* 'motion.teleop-mode' - 
     (bit, out) TRUE when motion is in 'teleop mode', as opposed to
    'coordinated mode'

* 'motion.tooloffset.x ... motion.tooloffset.w' - 
     (float, out, one per axis) shows the tool offset in effect;
     it could come from the tool table ('G43' active), or it could
     come from the gcode ('G43.1' active)

* `motion.spindle-orient-angle` -
	(float,out) Desired spindle orientation for M19. Value of the
	M19 R word parameter plus the value of the [RS274NGC]ORIENT_OFFSET ini parameter.

* `motion.spindle-orient-mode` -
	(s32,out) Desired spindle rotation mode M19. Default 0.

* `motion.spindle-orient` -
	(out,bit)
	Indicates start of spindle orient cycle. Set by M19. Cleared by any of M3,M4,M5. 
	If spindle-orient-fault is not zero during spindle-orient
	true, the M19 command fails with an error message.

* `motion.spindle-is-oriented` -
	(in, bit) Acknowledge pin for spindle-orient. Completes orient
	cycle. If spindle-orient was true when spindle-is-oriented was
	asserted, the spindle-orient pin is cleared and the
	spindle-locked pin is asserted. Also, the spindle-brake pin is asserted.

* `motion.spindle-orient-fault` -
	(s32, in) Fault code input for orient cycle. Any value other
	than zero  will cause the orient cycle to abort.

* `motion.spindle-lock` -
	(bit, out) Spindle orient complete pin. Cleared by any of M3,M4,M5. 

==== HAL pin usage for M19 orient spindle

Conceptually the spindle is in one of the following modes:

 - rotation mode (the default)
 - searching for desired orientation mode
 - orienation complete mode.

When an M19 is executed, the spindle changes to 'searching for desired
orientation' , and the `spindle-orient` HAL pin is asserted.  The
desired target position is specified by the `spindle-orient-angle` and
`spindle-orient-fwd` pins and driven by the M19 R and P parameters.

The HAL support logic is expected to react to `spindle-orient` by
moving the spindle to the desired position. When this is complete, the
HAL logic is expected to acknowledge this by asserting the
`spindle-is-oriented` pin.

Motion then acknowledges this by deasserting the `spindle-orient` pin
and asserts the `spindle-locked` pin to indicate 'orientation
complete' mode. It also raises the `spindle-brake` pin. The spindle now
is in 'orientation complete' mode.

If, during `spindle-orient` being true, and `spindle-is-oriented` not
yet asserted the `spindle-orient-fault` pin has a value other than
zero, the M19 command is aborted, a message including the fault code
is displayed, and the motion queue is flushed. The spindle reverts to
rotation mode.

Also, any of the M3,M4 or M5 commands cancel either 'searching for
desired orientation' or 'orientation complete' mode. This is indicated
by deasserting both the `spindle-orient` and `spindle-locked` pins.

The `spindle-orient-mode` pin reflects the M19 P word and shall be
interpreted as follows: 

 - 0: rotate clockwise or counterclockwise for smallest angular movement
 - 1: always rotate clockwise 
 - 2: always rotate counterclockwise

It can be used with the `orient` HAL component which provides a PID
command value based on spindle encoder positon, `spindle-orient-angle`
and `spindle-orient-mode`.

=== 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.

=== 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 LinuxCNC motion controller

== Axis (Joints)

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'.footnote:[In 'trivial kinematics' machines,
there is a one-to-one correspondence between joints and axes.] 
They are read and updated by the 'motion-controller' function.

=== Pins (((axis (HAL 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) 

=== Parameters

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

== iocontrol

iocontrol − accepts NML I/O commands, interacts with HAL in userspace.

The signals are turned on and off in userspace - if you have strict
timing requirements or simply need more i/o, consider using the realtime
synchronized i/o provided by <<sec:motion,motion>> instead.

=== Pins (((iocontrol (HAL 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.