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Endstop Related

This page explains the wiring, configuration, and status checking methods for common endstop types. Before the first homing, please complete the endstop status check to confirm the trigger logic is correct.

Safety Reminder
  • Endstop wiring operations must be performed with power disconnected.
  • Before homing, move the print head to the center of the machine and prepare an emergency stop or power disconnect.
  • Do not execute G28 if the endstop status is incorrect, as it may cause a crash.

Microswitch Endstop​

Three-Wire Microswitch Precautions​

Danger

Attention FLY motherboard users: Three-wire microswitch endstops cannot be directly connected to FLY motherboards. The motherboard endstop interface already provides 5V power. Incorrect wiring of a three-wire microswitch may cause a 5V short circuit, damaging the motherboard, host computer, or driver.

Solution:

  • Cut the 5V wire, typically the red one, in the XH2.54 connector of the three-wire endstop. Confirm the wire order in practice.
  • Wrap the cut end with insulating tape or heat shrink tubing to prevent short circuits.
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Microswitch Endstop Wiring Method​

Caution

The use of Normally Closed (NC) contacts is strongly recommended. NC wiring makes anomalies more apparent when a wire breaks, reducing the risk of a crash.

Motherboard TerminalFunctionConnection Requirement
5VPowerLeave unconnected
GNDGroundMust be connected
SSignalMust be connected

Testing Steps:

  1. Set the multimeter to continuity test mode.
  2. Test the normally closed terminal and common terminal of the microswitch.
  3. When not pressed, it should be conductive, and the buzzer should sound.
  4. When pressed, it should be open circuit, with no buzzer sound.
  5. If the result is opposite, check if the normally open (NO) terminal was used by mistake, or if there is poor contact.
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Microswitch Endstop Reference Configuration​

Most endstops require a pull-up resistor, so add ^ before the pin. When using NC endstops, you typically also need to add ! to invert the state.

printer.cfg
[stepper_x]
endstop_pin: ^!PD9

TAP​

Wiring Instructions​

Danger
  • This tutorial uses the BL-Touch interface of the SHT36-V2 as an example.
  • Some TAPs support 12V or 24V, but 5V power supply is recommended as a priority.
  • The middle signal port of the BL-Touch cannot be used as an endstop port.
Motherboard TerminalFunctionConnection Requirement
5VPowerMust be connected
GNDGroundMust be connected
SSignalMust be connected
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TAP Reference Configuration​

printer.cfg
[stepper_z]
endstop_pin: probe:z_virtual_endstop
# position_endstop: -0.5

[probe]
pin: ^sht36:PC15
x_offset: 0
y_offset: 0
# z_offset: 0
speed: 3.0
lift_speed: 5
samples: 3
samples_result: median
sample_retract_dist: 3.0
samples_tolerance: 0.075
samples_tolerance_retries: 3
activate_gcode:
    {% set PROBE_TEMP = 150 %}
    {% set MAX_TEMP = PROBE_TEMP + 5 %}
    {% set ACTUAL_TEMP = printer.extruder.temperature %}
    {% set TARGET_TEMP = printer.extruder.target %}

    {% if TARGET_TEMP > PROBE_TEMP %}
        { action_respond_info('Extruder temperature target of %.1fC is too high, lowering to %.1fC' % (TARGET_TEMP, PROBE_TEMP)) }
        M106 S255
        M109 S{ PROBE_TEMP }
        M106 S26
    {% else %}
        {% if ACTUAL_TEMP > MAX_TEMP %}
            { action_respond_info('Extruder temperature %.1fC is still too high, waiting until below %.1fC' % (ACTUAL_TEMP, MAX_TEMP)) }
            TEMPERATURE_WAIT SENSOR=extruder MAXIMUM={ MAX_TEMP }
        {% endif %}
    {% endif %}

Optical Endstop​

Danger
  • This tutorial uses the EE-SX670WR as an example.
  • The sensor type is NPN Normally Closed.
  • The optical switch uses 5V power.
  • If 12V or 24V power is required, refer to the proximity switch wiring method below.

Wiring Instructions​

Motherboard TerminalFunctionConnection Requirement
5VPowerMust be connected
GNDGroundMust be connected
SSignalMust be connected

EE-SX670WR Wiring Recommendations:

Optical SwitchFunctionConnection Requirement
BrownPowerMust be connected
BlueGroundMust be connected
BlackSignalMust be connected
PinkNormally ClosedConnect to GND to use NC function
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Optical Endstop Reference Configuration​

printer.cfg
[stepper_x]
endstop_pin: ^PD9

Proximity Switch​

Danger

Using the Omron proximity switch TL-Q5MC2-Z as an example, please note before operation:

  • The sensor type is NPN Normally Closed.
  • A BAT85 diode is required.
  • Exposed wire ends must be properly insulated to prevent short circuits.

Wiring Steps​

  1. Connect the black end (cathode) of the diode to the sensor signal wire.
  2. Connect the other end (anode) of the diode to the motherboard signal interface.
  3. Wrap the exposed wire ends with heat shrink tubing or electrical tape.
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Proximity Switch Reference Configuration​

printer.cfg
[probe]
pin: ^PC0
x_offset: 0
y_offset: 25.0
z_offset: 0

Endstop Status Check​

Preparation​

  1. After powering off, manually move the print head to the center of the machine.
  2. Power on and open the web console.
  3. Enter the following command to check endstop status:
QUERY_ENDSTOPS

When wiring and configuration are correct, untriggered endstops should show as open.

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Trigger Test​

Press and hold one of the endstop switches without releasing it, then execute again:

QUERY_ENDSTOPS

The status of the pressed endstop should change to TRIGGERED. For example, when pressing the Y endstop, the Y status should change from OPEN to TRIGGERED.

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Result Diagnosis​

SymptomAction
Status unchangedCheck the endstop switch wiring and the pin in the configuration
Trigger insensitiveCheck if the pull-up symbol ^ is added before the pin, e.g., ^PC0
Status invertedCheck if the invert symbol ! needs to be added or removed before the pin

When the status is inverted:

  • If currently ^!PD9, try changing to ^PD9.
  • If currently ^PD9, try changing to ^!PD9.
Extended Features

If the printer does not use physical endstop switches, please refer to Using Without Endstops Guide.

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