Description
Woodward 8200-505
Technical Specifications
- Part Number: 8200-505
- Signal Input: 4-20 mA analog control signal
- Power Supply: 24 VDC nominal
- Output: Pneumatic or electro-hydraulic pilot signal
Functional Features
- Closed-Loop Positioning: Continuously compares actual valve position with commanded position and adjusts output to eliminate error.
- Auto-Calibration: Features automatic calibration routines to adapt to actuator friction and hysteresis.
- Diagnostic Capabilities: Provides real-time feedback on valve position, travel deviation, and actuator health.
Application Scenarios
Deployed in steam turbine inlet valve control, extraction valve positioning, and gas turbine fuel valve modulation.
Performance Parameters
- Positioning Accuracy: Typically within ±0.1% of full stroke.
- Response Time: Fast dynamic response for tight process control.
Material Composition
Industrial-grade aluminum housing with precision-machined internal pneumatic components and conformal-coated electronics.
Structural Characteristics
- Compact Design: Space-efficient mounting directly on actuator or via bracket.
- Visual Indicators: Local LED indicators for power, position, and alarm status.
Working Principle
The positioner receives a 4-20 mA command from the controller and uses an internal position sensor (LVDT or potentiometer) to measure actual valve position. A microprocessor calculates the error and drives a pilot valve to adjust actuator pressure until the valve reaches the commanded position.
Installation Requirements
- Mechanical Linkage: Ensure the feedback linkage is properly aligned and free of binding.
- Air Supply: Provide clean, dry instrument air at the specified pressure.
Usage Precautions
- Calibration: Perform full auto-calibration after installation or actuator replacement.
- Air Quality: Ensure instrument air meets ISO 8573-1 Class 2.2.2 or better.
