4-layer FR4 PCB is engineered for critical metro station signal monitoring controllers, where precision, durabilité, and electromagnetic compatibility (EMC) are essential for safe railway operations. Avec des dimensions de 85mm×60mm et un 1.55mm d'épaisseur, the board provides a compact yet robust platform for integrating microcontrollers, communication interfaces, and signal conditioning circuitry in automated control cabinets. Construit à partir de Matériau FR4, Il offre une isolation électrique stable (constante diélectrique εr = 4,5) et résistance mécanique, suitable for operation in harsh railway environments with vibration, temperature fluctuations, et interférence électromagnétique.
Le 0.5Oz (18μm) épaisseur de cuivre on all layers balances fine-line routing density (ligne / espace minimum: 50µm / 50 mm) with signal integrity, ideal for high-speed digital interfaces (Par exemple, CANbus, Ethernet) and low-power microcontroller circuits. Le 4-architecture de calque (2 Couches de signalisation + 2 ground/power planes) minimizes EMI by isolating sensitive analog signals from digital noise, critical for reliable detection of train signals, track occupancy, and safety interlocks. Le Masque de soudure LPI verte protects against moisture and contaminants, Pendant que le Écran à soigneux blanc ensures clear component identification for maintenance in the field. Le Accepter (Or d'immersion nickel électrolaire) surface treatment provides a corrosion-resistant, solder-friendly finish (3-5μm nickel, 0.05-0.1μm gold), ensuring long-term reliability for both surface-mount (Smt) and through-hole (TREMPER) composants.
- EMC/EMI Mitigation:
- Ground plane stitching vias every 5mm to reduce loop inductance and suppress radiated emissions.
- Guard traces with via fences around sensitive analog inputs (Par exemple, track circuit receivers).
- Ferrite beads and bypass capacitors on power lines to filter switching noise.
- Mixed SMT/DIP Assembly:
- Composants SMT (ICS, resistors, condensateurs) for high-density digital circuitry.
- DIP connectors (Par exemple, DB9, RJ45) and relays for robust field connections and high-current switching.
- Gestion thermique:
- Thermal vias under power components (Par exemple, regulators, drivers) to dissipate heat into ground planes.
- Copper pour areas for passive cooling, maintaining <40°C temperature rise under full load.
- Fabrication de haute précision:
- Imagerie directe laser (LDI) for 50μm line/space accuracy in high-speed signal traces.
- Electroless nickel plating with ±10% thickness uniformity across all pads.
- Tester les protocoles:
- 100% AOI inspection for solder mask coverage and silkscreen clarity.
- Test de sonde volante pour la continuité et l'isolement électriques (≥ 100mΩ).
- In-circuit testing (TIC) to verify component placement and functionality.
- EMC testing per EN 50121-3-2 (railway electromagnetic compatibility standards).
- Conformité:
- UL 94V-0 flammability rating for FR4 material.
- RoHS and REACH compliant for hazardous substance restrictions.
- Track Circuit Monitoring:
Processes signals from track circuits to detect train presence and position, critical for block signaling systems.
- Level Crossing Control:
Controls safety barriers and warning signals at railway crossings, interfacing with sensors and relays.
- Train Detection Systems:
Monitors inductive loop detectors or axle counters to verify train movements and occupancy.
- Interfaces de communication:
Manages data exchange between control cabinets, central control systems, and onboard train electronics.
By integrating 4-layer EMI shielding, 0.5OZ copper precision, et la durabilité en énig, this PCB enables engineers to build reliable, compliant metro signal monitoring controllers. The mixed SMT/DIP assembly supports both high-density digital integration and robust field connections, while the compact form factor fits seamlessly into space-constrained control cabinets. Soutenu par ISO 9001:2015 certification and compliance with railway standards, this PCB ensures consistent performance in the critical safety systems that underpin modern metro operations.
