My-Cloner Rev A — Motors & Homing¶

See Owner-Reported Hardware and Test Status for the confirmed V3.0 hardware, connections and remaining checks.

This page describes the stepper motor architecture, driver assignments and homing strategy used by the My-Cloner Rev A.

The printer uses:

5 × stepper motors
5 × TMC2209 stepper drivers
UART communication
Sensorless homing on X and Y
P.I.N.D.A. V1 probe for Z reference

Physical Validation Required

Motor direction, current, sensorless-homing sensitivity and homing repeatability must be validated on the physical My-Cloner Rev A.

Configuration values must not be considered final until the machine has completed the bring-up and validation process.

Motor Architecture¶

The My-Cloner Rev A uses five stepper motors.

Function	Motor Type	Board Driver	Klipper Section
X Axis	NEMA17	X	`[stepper_x]`
Y Axis	NEMA17	Y	`[stepper_y]`
Left Z Axis	NEMA17	Z	`[stepper_z]`
Right Z Axis	NEMA17	E1	`[stepper_z1]`
Extruder	NEMA17 Pancake	E0	`[extruder]`

The Z axis uses two independent motors.

The current Rev A board assignment is:

Z driver → left Z motor; E1 driver → right Z motor.

This assignment will be physically validated during machine bring-up.

graph TD
    BOARD[MKS Robin Nano V3]

    XDRV[X Driver<br/>TMC2209]
    YDRV[Y Driver<br/>TMC2209]
    ZDRV[Z Driver<br/>TMC2209]
    E0DRV[E0 Driver<br/>TMC2209]
    E1DRV[E1 Driver<br/>TMC2209]

    XM[X Axis Motor]
    YM[Y Axis Motor]
    ZLM[Left Z Motor]
    EXT[Extruder Motor]
    ZRM[Right Z Motor]

    BOARD --> XDRV
    BOARD --> YDRV
    BOARD --> ZDRV
    BOARD --> E0DRV
    BOARD --> E1DRV

    XDRV --> XM
    YDRV --> YM
    ZDRV --> ZLM
    E0DRV --> EXT
    E1DRV --> ZRM

Stepper Drivers¶

The My-Cloner Rev A uses:

5 × TMC2209

The drivers are intended to operate in:

UART mode

This allows Klipper to configure and monitor driver parameters directly.

The MKS Robin Nano V3 provides individual UART lines for each driver position.

Driver	UART Pin
X	`PD5`
Y	`PD7`
Z	`PD4`
E0	`PD9`
E1	`PD8`

These assignments are documented in the My-Cloner I/O Map.

Driver Configuration¶

The final TMC2209 configuration will include parameters such as:

UART pin
Motor current
Interpolation
StealthChop / SpreadCycle behaviour where appropriate
StallGuard configuration
Sensorless-homing sensitivity

Example structure:

[tmc2209 stepper_x]
uart_pin: PD5
diag_pin: PA15
run_current: TBD
driver_SGTHRS: TBD

Do Not Copy Example Values

The UART and DIAG MCU pins are known from the MKS Robin Nano V3 board mapping.

The final Klipper diag_pin configuration may require pull-up or signal inversion depending on the physical TMC2209 installation and DIAG behaviour.

Motor current and StallGuard sensitivity depend on the actual motors and mechanical system and must be determined during physical testing.

STEP / DIR / ENABLE Mapping¶

X Axis¶

Signal	MCU Pin
STEP	`PE3`
DIR	`PE2`
ENABLE	`PE4`
UART	`PD5`
DIAG / Endstop	`PA15`

The final direction polarity will be determined during motor testing.

Y Axis¶

Signal	MCU Pin
STEP	`PE0`
DIR	`PB9`
ENABLE	`PE1`
UART	`PD7`
DIAG / Endstop	`PD2`

The final direction polarity will be determined during motor testing.

Left Z Axis¶

Signal	MCU Pin
STEP	`PB5`
DIR	`PB4`
ENABLE	`PB8`
UART	`PD4`

The Left Z motor uses the board's standard Z driver position.

Right Z Axis¶

Signal	MCU Pin
STEP	`PD15`
DIR	`PA1`
ENABLE	`PA3`
UART	`PD8`

The Right Z motor uses the board's E1 driver position.

In Klipper this will be configured as:

[stepper_z1]

Independent Z Motors

The two Z motors are controlled independently by Klipper.

This allows separate motor control while still operating as one Z axis.

Extruder¶

Signal	MCU Pin
STEP	`PD6`
DIR	`PD3`
ENABLE	`PB3`
UART	`PD9`

The extruder uses the E0 driver position.

X and Y Sensorless Homing¶

The My-Cloner Rev A does not use physical X or Y endstop switches.

Instead, the Rev A architecture uses:

TMC2209 sensorless homing

Sensorless homing detects the mechanical end of travel using the driver's StallGuard functionality.

The sensorless-homing architecture is defined for Rev A, but the final driver current, StallGuard sensitivity, homing speed and repeatability must be determined during physical bring-up.

The MKS Robin Nano V3 routes the TMC2209 DIAG signals to the endstop inputs.

Axis	DIAG / Endstop	MCU Pin
X	X-	`PA15`
Y	Y-	`PD2`

graph LR
    XMotor[X Axis Motor] --> XDriver[TMC2209 X]
    XDriver -->|StallGuard| XDiag[X DIAG]
    XDiag -->|PA15| MCU[MKS Robin Nano V3]

    YMotor[Y Axis Motor] --> YDriver[TMC2209 Y]
    YDriver -->|StallGuard| YDiag[Y DIAG]
    YDiag -->|PD2| MCU

Sensorless Homing Parameters¶

Sensorless homing requires physical tuning.

The main variables include:

Motor current
driver_SGTHRS
Homing speed
Belt tension
Mechanical friction
Axis mass
Acceleration
Homing direction

A configuration that works on another printer must not be assumed to work correctly on the My-Cloner.

Too Sensitive

If the StallGuard threshold is too sensitive, the axis may stop before reaching the mechanical end.

Not Sensitive Enough

If the threshold is not sensitive enough, the motor may continue pushing against the frame after reaching the mechanical end.

The value must therefore be tuned conservatively.

Sensorless Homing Validation¶

The recommended validation process for each sensorless axis is:

Confirm free mechanical movement.
Verify motor direction at low speed.
Confirm TMC2209 UART communication.
Configure a conservative motor current.
Configure the DIAG pin.
Start with a conservative StallGuard threshold.
Test homing at low speed.
Adjust sensitivity gradually.
Repeat homing multiple times.
Confirm repeatability.

The final configuration should only be accepted when homing is reliable and repeatable.

Homing Direction¶

The final X and Y homing directions must match the My-Cloner mechanical design.

The direction will be validated against:

Axis geometry
Motor direction
Belt routing
Coordinate system
Printable-area origin

The Klipper dir_pin polarity may therefore require inversion during bring-up.

Pin Inversion

In Klipper, the ! prefix is used to invert a digital signal.

Example:

dir_pin: !PE2

The required polarity must be determined from the actual motor movement.

Z Homing¶

The Z axis does not use TMC sensorless homing.

The My-Cloner Rev A uses a:

P.I.N.D.A. inductive probe

The probe provides:

Z reference
Bed probing
Bed-mesh measurements

graph TD
    PINDA[P.I.N.D.A. V1] -->|Z- / PC8| MCU[MKS Robin Nano V3]
    MCU --> KLIPPER[Klipper]

    KLIPPER --> ZDRV[Z Driver]
    KLIPPER --> E1DRV[E1 Driver]

    ZDRV --> ZL[Left Z Motor]
    E1DRV --> ZR[Right Z Motor]

The owner reports P.I.N.D.A. V1 on Z- / PC8, GND and 5 V, and confirms response to metal. Klipper trigger polarity, offsets and repeatability remain pending validation.

Z Motor Behaviour¶

Both Z motors move together during normal operation.

Klipper will configure them as:

[stepper_z]

and:

[stepper_z1]

The P.I.N.D.A. probe provides the Z reference used by the Z axis.

Z Motor Direction

Both Z motors must move the gantry in the same physical direction.

Depending on motor orientation and wiring, one motor may require reversed direction.

Verify both motors independently before performing normal Z moves.

Motor Direction Validation¶

Before homing any axis:

Position the carriage away from the mechanical end.
Command a small positive move.
Observe the physical direction.
Stop immediately if the direction is incorrect.
Correct the Klipper direction polarity or motor wiring.
Repeat with a small move.
Validate each motor independently.

For the Z axis, test Left Z and Right Z independently before operating them together.

Motor Current¶

The four axis motors are 17HS13-0404S1, rated 0.4 A per phase by the manufacturer. The extruder motor is 17HS10-0704S, rated 0.7 A per phase. These ratings are not final Klipper run_current settings; operating currents remain pending selection and testing.

Motor current must be selected according to:

Motor rated current
Driver cooling
Mechanical load
Required torque
Operating temperature
Reliability

The final current values will be recorded after physical validation.

Motor	`run_current`	Status
X	TBD	Pending validation
Y	TBD	Pending validation
Left Z	TBD	Pending validation
Right Z	TBD	Pending validation
Extruder	TBD	Pending validation

Microstepping¶

The generic MKS Robin Nano V3 Klipper configuration uses:

microsteps: 16

This is a suitable starting point for the Rev A configuration.

The final configuration must remain consistent with:

TMC2209 settings
Pulley geometry
Belt pitch
Lead-screw geometry
Extruder geometry

Mechanical Transmission¶

X and Y¶

The mechanical BOM specifies GT2 belts and 20-tooth pulleys, confirmed by the owner. With 2 mm belt pitch, the nominal travel is 40 mm per pulley revolution. Verify actual motion during calibration.

Z¶

The installed lead screws have 2 mm pitch and 8 mm lead. Nominal Z travel is 8 mm per revolution; use the lead, not the thread pitch, when deriving rotation_distance.

Extruder¶

The owner confirms direct motor-to-drive-gear operation without reduction. Extruder rotation_distance must still be calibrated physically; do not assume a geared extruder ratio.

The generic Klipper value must not be treated as the final My-Cloner value.

Bring-Up Sequence¶

The recommended motor bring-up sequence is:

Validate controller power.
Validate USB / MCU communication.
Confirm TMC2209 UART communication.
Test X motor direction.
Test Y motor direction.
Test Left Z motor direction.
Test Right Z motor direction.
Test extruder motor direction.
Configure motor currents.
Configure X sensorless homing.
Configure Y sensorless homing.
Validate P.I.N.D.A. input.
Validate Z homing.
Test repeated homing cycles.

Do not attempt a full automatic homing sequence until each subsystem has been tested individually.

Validation Status¶

See Status Definitions. Design assignments and source mappings do not establish physical validation.

Item	Status
X motor board mapping	Source confirmed
Y motor board mapping	Source confirmed
Left Z board mapping	Source confirmed
E0 / Extruder mapping	Source confirmed
E1 / Right Z mapping	Rev A assignment
TMC2209 UART pins	Source confirmed
X sensorless architecture	Rev A assignment
Y sensorless architecture	Rev A assignment
Z homing architecture	Rev A assignment — P.I.N.D.A.
Motor directions	Pending validation
Motor currents	Pending validation
X StallGuard threshold	Pending validation
Y StallGuard threshold	Pending validation
Homing speeds	Pending validation
Homing repeatability	Pending validation
Z motor synchronization	Pending validation
Extruder rotation distance	Pending validation

I/O Map — complete motor, UART, DIAG and probe mapping
Controller Board — MKS Robin Nano V3 driver and endstop interfaces
Heaters & Temperature Sensors — P.I.N.D.A. context and thermal-system documentation
Firmware Configuration — planned Klipper motor and homing configuration

My-Cloner Rev A — Motors & Homing¶

Motor Architecture¶

Stepper Drivers¶

Driver Configuration¶

STEP / DIR / ENABLE Mapping¶

X Axis¶

Y Axis¶

Left Z Axis¶

Right Z Axis¶

Extruder¶

X and Y Sensorless Homing¶

Sensorless Homing Parameters¶

Sensorless Homing Validation¶

Homing Direction¶

Z Homing¶

Z Motor Behaviour¶

Motor Direction Validation¶

Motor Current¶

Microstepping¶

Mechanical Transmission¶

X and Y¶

Z¶

Extruder¶

Bring-Up Sequence¶

Validation Status¶

Related Documentation¶