Sensor Wiring Setup
0:03
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
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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.
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