Building a hydraulic pressure test bench for aerospace or defence qualification testing isn't just a plumbing exercise. The control system design determines whether you get ±0.1% pressure accuracy and EN 13849-compliant safety — or an unsafe rig that fails its first audit. Control Architecture Pressure Setpoint (HMI/PLC) │ ▼ PID Controller (in PLC) │ ▼ Servo Proportional Valve ──→ Hydraulic Circuit ──→ DUT ▲ │ │ │ └────── Pressure Feedback (transducer, 0-10V or 4-20mA) Enter fullscreen mode Exit fullscreen mode For aerospace-grade accuracy: use a 16-bit ADC for pressure transducer input. A 700 bar range with 16-bit resolution gives 0.01 bar resolution — well within the ±0.1% target. PID Tuning for Hydraulic Systems Hydraulic systems are challenging for PID control due to nonlinear flow characteristics and fluid compressibility.…