Sensor Wiring Setup
Thought for 3 sec
Work done
- Integrated the two native PC817 homing sensor channels with labeled X/Y sensor terminals, 10kΩ pullups, 100nF filters, 4.7kΩ status LED resistors, Nano D9/D10 outputs, and a single 0Ω star link between
GND_24VandGND_LOGIC. - Preserved the 100 mm × 152 mm, 2-layer board and placed the new/updated sensor parts in the connector area with no placement overlap or out-of-bounds issues.
- Applied the required 1.6 mm copper spacing rule conservatively and documented the implementation in Homing Sensor Integration Audit.
- ✅ Native X/Y sensor circuitry integrated and connected to
+24V_SENSOR/GND_24V. - ✅
LIMIT_X_NETconnects to Nano D9;LIMIT_Y_NETconnects to Nano D10. - ✅ Sensor terminals are documented as BRN/BLU/BLK and filters/status LEDs are included.
- ✅ Board size and 2-layer stackup are preserved.
- ❌ Final layout DRC is not clean: airwires and overlapping copper remain after the stricter spacing rule, so the board is not fabrication-ready yet.
Run routing cleanup/autoroute for the updated board, then re-check DRC until the airwire and copper-clearance issues are cleared. I can continue with PCB routing/cleanup guidance next.
Route sensor nets
Review DRC violations
Verify clearance rule
Prepare Gerbers
Update audit doc
Refine this doc
Ask about this doc
Homing Sensor Integration Audit
Summary
Two native PC817 homing sensor channels are integrated on the PCB for X and Y using shared +24V_SENSOR and GND_24V rails, with Nano limit outputs on D9 and D10.
Schematic implementation
- X channel:
- Connector: J_SENS_X, 3-position 5.08 mm terminal
- Pin mapping: Pin 1 BRN = +24V_SENSOR, Pin 2 BLU = GND_24V, Pin 3 BLK = SENSOR_BLACK_X
- Optocoupler: U_SENS_X, PC817 DIP-4
- Pullup: R_PULLUP_X = 10 kΩ, 0.25 W from +24V_SENSOR to SENSOR_BLACK_X
- Filter: C_FILT_X = 100 nF from SENSOR_BLACK_X to GND_24V
- Status LED: LED_STATUS_X with R_STATUS_X = 4.7 kΩ from SENSOR_BLACK_X to GND_24V
- Logic output: LIMIT_X_NET connects U_SENS_X pin 4 to Nano D9 and NANO_SOCKET_A pin 12
- Y channel:
- Connector: J_SENS_Y, 3-position 5.08 mm terminal
- Pin mapping: Pin 1 BRN = +24V_SENSOR, Pin 2 BLU = GND_24V, Pin 3 BLK = SENSOR_BLACK_Y
- Optocoupler: U_SENS_Y, PC817 DIP-4
- Pullup: R_PULLUP_Y = 10 kΩ, 0.25 W from +24V_SENSOR to SENSOR_BLACK_Y
- Filter: C_FILT_Y = 100 nF from SENSOR_BLACK_Y to GND_24V
- Status LED: LED_STATUS_Y with R_STATUS_Y = 4.7 kΩ from SENSOR_BLACK_Y to GND_24V
- Logic output: LIMIT_Y_NET connects U_SENS_Y pin 4 to Nano D10 and NANO_SOCKET_A pin 13
Grounding and power
- J_SENSOR_PWR pin 1 is +24V_SENSOR.
- J_SENSOR_PWR pin 2 is GND_24V.
- PC817 input cathodes, sensor blue terminals, filter returns, and status LED cathodes use GND_24V.
- PC817 output emitters use GND_LOGIC.
- R_STAR_GND is a 0 Ω 0805 star link between GND_24V and GND_LOGIC.
- J_SENSOR_PWR role notes specify direct PSU sensor power, not the LC1-D09BD switched output.
Polarity
The Nano input nets are collector outputs: LIMIT_X_NET to D9 and LIMIT_Y_NET to D10. The sensor black/input node is separate from the Nano logic output node for both channels. This supports active-high firmware behavior when the optocoupler transistor is off and the Nano input is pulled high by the existing input configuration.
PCB/layout updates
- Board remains 100 mm x 152 mm rectangular.
- Stackup remains Standard 2 Layer.
- Sensor terminals, optocouplers, filters, pullups, status LEDs, and R_STAR_GND were placed in the existing connector area.
- Universal copper keepout was updated to 1.6 mm to enforce the specified spacing conservatively.
Verification snapshot
- ERC checks reviewed: floating pin, single-pin net, missing power, and driver conflicts all pass.
- Manufacturing MPN check passes.
- Missing footprint check passes.
- DRC still reports route/copper issues after the stricter 1.6 mm clearance rule: overlapping copper and airwires remain. These require routing cleanup/autoroute rerun or manual trace edits before fabrication.
Remaining action before fabrication
Reroute/clean the PCB so the 1.6 mm clearance rule is satisfied and all airwires/overlapping copper DRC errors are cleared. The schematic-level homing sensor integration is complete, but the board is not fabrication-ready until layout DRC is clean.
Summary
Schematic implementation
Grounding and power
Polarity
PCB/layout updates
Verification snapshot
Remaining action before fabrication
