Struct Axis 

pub struct Axis {

    pub is_error: bool,
    pub error_code: u32,
    pub error_message: String,
    pub motor_on: bool,
    pub is_busy: bool,
    pub in_motion: bool,
    pub moving_positive: bool,
    pub moving_negative: bool,
    pub position: f64,
    pub raw_position: i64,
    pub speed: f64,
    pub at_max_limit: bool,
    pub at_min_limit: bool,
    pub at_positive_limit_switch: bool,
    pub at_negative_limit_switch: bool,
    pub home_sensor: bool,
    /* private fields */
}

Stateful motion controller for a CiA 402 servo drive.

Manages the CiA 402 protocol (state machine, PP handshake, homing) internally. Call tick() every control cycle to progress operations and update output fields.

Fields

is_error: bool

True if a drive fault or operation timeout has occurred.

error_code: u32

Drive error code (from status word or view error_code).

error_message: String

Human-readable error description.

motor_on: bool

True when the drive is in Operation Enabled state.

is_busy: bool

True when any operation is in progress (enable, move, home, fault recovery, etc.).

Derived from the internal state machine — immediately true when a command is issued, false when the operation completes or a fault cancels it. Use this (not in_motion) to wait for operations to finish.

in_motion: bool

True while a move operation specifically is active (subset of is_busy).

moving_positive: bool

True when velocity is positive.

moving_negative: bool

True when velocity is negative.

position: f64

Current position in user units (relative to home).

raw_position: i64

Current position in raw encoder counts (widened from i32).

speed: f64

Current speed in user units/s (absolute value).

at_max_limit: bool

True when position is at or beyond the maximum software limit.

at_min_limit: bool

True when position is at or beyond the minimum software limit.

at_positive_limit_switch: bool

True when the positive-direction hardware limit switch is active.

at_negative_limit_switch: bool

True when the negative-direction hardware limit switch is active.

home_sensor: bool

True when the home reference sensor is active.

Implementations

impl Axis

pub fn new(config: AxisConfig, device_name: &str) -> Self

Create a new Axis with the given configuration.

device_name must match the device name in project.json (used for SDO operations during homing).

pub fn config(&self) -> &AxisConfig

Get a reference to the axis configuration.

pub fn move_absolute( &mut self, view: &mut impl AxisView, target: f64, vel: f64, accel: f64, decel: f64, )

Start an absolute move to target in user units.

The axis must be enabled (Operation Enabled) before calling this. If the target exceeds a software position limit, the move is rejected and is_error is set.

pub fn move_relative( &mut self, view: &mut impl AxisView, distance: f64, vel: f64, accel: f64, decel: f64, )

Start a relative move by distance user units from the current position.

The axis must be enabled (Operation Enabled) before calling this. If the resulting position would exceed a software position limit, the move is rejected and is_error is set.

pub fn halt(&mut self, view: &mut impl AxisView)

Halt the current move (decelerate to stop).

pub fn enable(&mut self, view: &mut impl AxisView)

Start the enable sequence (Shutdown → ReadyToSwitchOn → OperationEnabled).

The sequence is multi-tick. Check motor_on for completion.

pub fn disable(&mut self, view: &mut impl AxisView)

Start the disable sequence (OperationEnabled → SwitchedOn).

pub fn reset_faults(&mut self, view: &mut impl AxisView)

Start a fault reset sequence.

Clears bit 7, then asserts it (rising edge), then waits for fault to clear.

pub fn home(&mut self, view: &mut impl AxisView, method: HomingMethod)

Start a homing sequence with the given homing method.

Integrated methods delegate to the drive’s built-in CiA 402 homing mode (SDO writes + homing trigger).

Software methods are implemented by the Axis, which monitors AxisView sensor signals for edge triggers and captures home.

pub fn set_position(&mut self, view: &impl AxisView, user_units: f64)

Set the current position to the given user-unit value.

Adjusts the internal home offset so that the current raw position maps to user_units. Does not move the motor.

pub fn set_software_max_limit(&mut self, user_units: f64)

Set the maximum (positive) software position limit.

pub fn set_software_min_limit(&mut self, user_units: f64)

Set the minimum (negative) software position limit.

pub fn sdo_write( &mut self, client: &mut CommandClient, index: u16, sub_index: u8, value: Value, )

Write an SDO value to the drive.

pub fn sdo_read( &mut self, client: &mut CommandClient, index: u16, sub_index: u8, ) -> u32

Start an SDO read from the drive. Returns a transaction ID.

pub fn sdo_result(&mut self, client: &mut CommandClient, tid: u32) -> SdoResult

Check the result of a previous SDO read.

pub fn tick(&mut self, view: &mut impl AxisView, client: &mut CommandClient)

Update outputs and progress the current operation.

Must be called every control cycle. Does three things:

1. Checks for drive faults
2. Progresses the current multi-tick operation
3. Updates output fields (position, velocity, status)

Outputs are updated last so they reflect the final state after all processing for this tick.