DC Board DRC Fixes
Worked for 2 mins 24 sec
Dangling trace cleanup is complete.
- Found 31 dangling-trace warnings.
- Deleted 60 trace stub nodes tied to those warnings.
- Re-ran dangling-trace DRC at 2026-05-15 22:12:22 UTC.
- Remaining dangling traces: 0
No schematic edits or connector moves were made.
Check the layout for unrouted nets after removing those stubs.
Thought for 13 sec
I’ll check the layout for unrouted nets by running the airwire DRC now, then I’ll report the current unrouted count and affected items without making routing changes.
Worked for 32 sec
Layout check found 33 unrouted airwire errors after the overlap and dangling-stub cleanup.
Current cleanup status:
- Overlapping copper: cleared to 0
- Dangling traces: cleared to 0
- Unrouted nets / airwires: 33 errors remain
Next step is routing those remaining airwires, preferably in phases: power/ground first, then signals.
Route power/ground
List unrouted nets
Recheck after routing
Route short signals
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Industrial Welding Machine IoT Controller Specification
Purpose
Retrofit PCB for inverter welding machines. The controller reports MQTT telemetry, arc hours, machine utilization, alarm/warning states, and GPS tracking while surviving high EMI and welding transients.
Functional Blocks
- Power and protection: 12V_AUX input, fuse, reverse polarity protection, 16V TVS surge clamp, common-mode/LC filtering, isolated DC-DC conversion, 5V_DIG, 3V3_DIG, and 3V3_ANA rails.
- Main controller: ESP32-WROOM-32 module for application firmware, WiFi, ADC/GPIO, UART modem control, and local diagnostics.
- Cellular/GNSS: SIM7600/EC200U-class LTE/GNSS modem with UART control, SIM interface, LTE antenna, GNSS antenna, and high-current local bulk capacitance.
- Isolated digital inputs: machine ON detection from 12V auxiliary sensing and fan RPM tach input through optocoupler/RC/TVS filtering.
- Analog and sensor inputs: Hall current sensor interface with RC + op-amp buffering to ESP32 ADC; three common-terminal NTC inputs with pull-ups, RC filtering, and ADC-compatible scaling.
- Isolated AC voltage monitoring: three-phase voltage sensing section isolated from ESP32 using opto/isolated front-end concept and ISO_GND boundary.
- Relay-enabled welding voltage sensing: relay contacts enable the weld-voltage divider/filter only when firmware detects Hall current above threshold.
- Connector block: 5.08mm industrial screw terminals for power, Hall, NTC common sensors, fan tach, AC phases, and welding voltage sense.
Selected Major Parts
- ESP32-WROOM-32E/32D module for WiFi and MCU.
- SIM7600E-H or EC200U LTE/GNSS module; SIM7600E-H selected as default due richer GNSS/cellular capability.
- IH1205S isolated DC-DC converter for 12V to isolated 5V generation; note 1W margin is tight for modem operation, so production design should validate modem peak current and may require a higher-power 12V input module if available.
- AP2112K-3.3 for local 3.3V digital regulation from 5V_DIG.
- PC817/PC847 optocouplers for isolated status/tach/phase sensing.
- LMV358 for Hall/analog buffering.
- SMBJ16A/SMAJ16A TVS for 12V input; TVS/ESD arrays or discrete clamps at all external signal connectors.
- TDK/Sunlord common-mode chokes for noisy external signal pairs and power entry.
- 5.08mm Phoenix/Kefa screw terminals for industrial field wiring.
Net Naming
Power nets: 12V_AUX, 12V_PROT, 5V_DIG, 3V3_DIG, 3V3_ANA, MODEM_VBAT.
Ground nets: DGND, AGND, ISO_GND, CHASSIS_SHIELD.
Signals: HALL_ADC, ARC_DETECT, NTC_IGBT_ADC, NTC_TRANSFORMER_ADC, NTC_HEATSINK_ADC, NTC_COMMON, FAN_TACH_ISO, MACHINE_ON_ISO, AC_PHASE_A/B/C, WELD_V_SENSE, WELD_SENSE_EN, MODEM_TX/RX, MODEM_PWRKEY, MODEM_STATUS.
Isolation Strategy
- Welding/machine-side signals enter through screw terminals into the ISO_GND domain.
- Optocouplers or isolated measurement front-ends transfer digital/phase status across the isolation boundary.
- Hall and NTC low-voltage sensors may use AGND with filtered entry only if their source is already low-energy and referenced to the machine control board; otherwise isolate them using external/current transducer modules.
- Maintain a routed isolation slot or keepout between ISO_GND and DGND/AGND. Do not bridge with copper pours.
- If chassis bonding is required, use a controlled single-point RC/Y-cap/TVS strategy, not a direct AGND-DGND-ISO_GND short.
PCB Stackup and Sectioning
Use a 6-layer PCB for EMI margin:
L1 components/signals, L2 DGND reference plane, L3 power plane, L4 signal/analog, L5 AGND/DGND controlled plane regions, L6 low-speed/connector routing.
Board zones: power entry at one edge, isolated field I/O along an opposite/side edge, ESP32 at board edge with antenna overhang and copper keepout, LTE/GNSS modem near antenna connectors, analog conditioning between field connectors and MCU but away from switching power.
Connector Recommendation
Use pluggable or fixed 5.08mm screw terminals, derated by 50% for continuous current. Put GND/common first where feasible. Keep AC phase and welding voltage connectors physically separated from low-voltage sensors.
Industrial Layout Rules
- Place TVS/ESD clamps immediately after connector pins before series resistors/filter components.
- Place common-mode chokes at cable entry points.
- Keep relay contact/welding voltage sense and AC phase networks away from ESP32 antenna and ADC traces.
- Route analog ADC traces short, guarded by AGND, with RC filters close to ADC/input buffers.
- Provide no copper under ESP32 antenna on all layers and place module antenna at board edge.
- Use wide power traces/pours for 12V_AUX, 5V_DIG, and modem supply; place bulk capacitance at modem supply pins.
- Provide mounting holes connected to chassis/shield only if enclosure bonding strategy is defined.
Firmware/Telemetry Requirements
- Publish MQTT telemetry: machine_on, arc_on, weld_current, arc_hours, utilization, three temperatures, fan_rpm, ac_phase_present flags, weld_voltage_when_enabled, alarm/warning bitfield, GPS position.
- Debounce/low-pass all opto inputs. Use Hall-current threshold plus hysteresis for arc detection and relay enable.
- Do not sample idle welding voltage unless WELD_SENSE_EN relay is closed after current threshold confirmation.
Purpose
Functional Blocks
Selected Major Parts
Net Naming
Isolation Strategy
PCB Stackup and Sectioning
Connector Recommendation
Industrial Layout Rules
Firmware/Telemetry Requirements
