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8. Wiring and Final Notes

X Endstop Wiring

Horizontal limit switch

Example of a mechanical limit switch from the BOM.

Overview

Mechanical limit switch PCBs (as above) have a 3-pin JST-XH connector with the following pins:

  1. Common (C)
  2. Normally Open (NO)
  3. Normally Closed (NC).

MCU endstop wire order example

MCU boards also have a 3-pin JST-XH connector for endstops, but they are typically wired as seen in the graphic at right:

  1. +5V
  2. GND
  3. SIG (pin 1.29 in the illustration)

Wiring the Endstop

Although both sides have a 3-pin connector, the endstop connection only needs two (2) wires. Unfortunately, limit switch PCBs are often sold with a 3-wire cable. This is hazardous if the +5V pin is connected to the endstop, and may start a fire.

Warning

Never connect a +5V pin to a mechanical endstop.

These are the correct pins to connect:

Pin Switch Pin Board Pin
1 C (to SIG) (Unused)
2 (Unused) SIG
3 NC (to GND) GND