4.1 Connect Limit Switches
Dry-contact switches, 5 V sensors, and industrial 12-24 V sensors
Power off before wiring. Every input header is Signal / GND / SW-VCC. Never put an external voltage directly on the Signal pin. Set the item 5 SW-VCC jumper before connecting powered sensors.
Input Map in the Test YAML
| Terminal | Assigned function | Terminal | Assigned function |
|---|
| GPIO.42 | X limit - | GPIO.41 | X limit + |
| GPIO.40 | Y limit - | GPIO.39 | Y limit + |
| GPIO.38/48 | Z limit - | GPIO.37 | A limit - |
| GPIO.36 | B limit - | GPIO.10 | C limit - |
| GPIO.47 | Probe | GPIO.3 | Toolsetter |
A. Standard Mechanical Switch
- Leave SW-VCC at the default 5 V.
- Connect the switch between Signal and GND; SW-VCC is not needed for a dry contact.
- Use the normally-closed contact where practical so a broken wire can be detected.
- Set the YAML pin polarity (
:low or no modifier) to match the chosen contact, then verify with $limits.
B. Three-wire 5 V Sensor
Set SW-VCC to 5 V. Connect sensor VCC to SW-VCC, sensor GND to GND, and sensor output to Signal. Confirm the output is compatible with a 5 V input before power-on.
C. Three-wire 12-24 V Sensor
Set SW-VCC to Vmot-Main, and power the board from the same 12-24 V required by the sensor. Connect VCC / GND / output to the matching three pins. VIN Main and SW-VCC must never exceed 24 V.
PNP and NPN sensors produce opposite active states. Change the YAML pin inversion only after checking the idle and triggered state in $limits.
D. Mixed Sensor Voltages
SW-VCC is one global selection for all ten input headers. It cannot provide 5 V on one header and 24 V on another at the same time. For a mixed system, power the second sensor group from a separate suitable supply, join signal ground only where the equipment design permits, and leave those sensors' SW-VCC pins unconnected. If unsure, use isolated interface modules.
Acceptance check: each input is inactive at rest, changes state only when its switch is operated, and returns cleanly when released. Complete the bench test in section 2.5 before connecting the machine.