Case
Healthcare Facility Project：Shenzhen Nanshan Hospital
PLC Control Cabinets in Hospital Applications: Critical Functions & Implementations
- Core Application Scenarios
A. Life Support Systems
Medical Gas Control
Function: Regulates O₂/N₂O/Vacuum pressures (0.4–0.55MPa) with <1% fluctuation
PLC Role: Monitors pipeline pressure via analog inputs (4-20mA), triggers alarms if thresholds breached (EN ISO 7396-1)
Safety: Automatic shutoff during fire alarms (NFPA 99 compliance)
HVAC for OR/ICU
Precision Control: Maintains ISO Class 5 air cleanliness with 20-24°C, 40-60% RH
PLC Logic: VFD-driven laminar flow control (0.25-0.35m/s velocity) with HEPA filter DP monitoring
B. Power Management
Critical Load Transfer
Implementation: Automatic genset startup (<10s) upon grid failure (UL 1008)
PLC Logic: Dual-source ATS with closed-transition switching
Harmonic Mitigation
Solution: PLC-controlled active filters reduce MRI/CT harmonics to <5% THD
C. Laboratory Automation
Biosafety Cabinets
Control: Maintains 0.5m/s face velocity with dynamic sash positioning
Data Logging: Stores 21 CFR Part 11-compliant operation records
- Specialized Control Requirements
EMC Considerations
Shielding: MIL-STD-461G compliant enclosures for MRI zones
Noise Immunity: Optical isolation for ECG/EEG equipment (IEC 60601-1-2)
Redundancy Design
Architecture: Dual hot-standby CPUs (SIL 3) for dialysis machines
Failsafe: Watchdog timers with <100ms failover
- Operational Benefits
Patient Safety
Prevents anesthetic gas mix errors through interlocked valve control
Energy Efficiency
Achieves 30% HVAC energy savings via occupancy-based ventilation
Maintenance Optimization
Predictive algorithms detect pump bearing wear (vibration FFT analysis)
- Implementation Examples Department PLC Model Key I/O Configuration OR Suites Siemens S7-1500 16 AI (PT100), 32 DO (24VDC) Pharmacy Allen-Bradley CompactLogix 8-axis servo control Central Sterile Omron NJ501 EtherCAT-connected SCARA robots
- Emerging Trends
Medical IoT Integration
PLCs streaming equipment data to Azure Digital Twins for predictive maintenance