WOODWARD 5437-523 Digital Servo / Actuator Driver

Description

1. Core Overview & Positioning

2. Key Features & Functions

• Servo Amplifier:​ Provides the necessary current/voltage to drive inductive loads of servo valve coils or actuator motors.
• Closed-Loop Control:​ Executes a fast, inner control loop using position feedback​ from an LVDT (Linear Variable Differential Transformer) or RVDT (Rotary Variable Differential Transformer) to achieve precise positioning.
• Dual Inputs:​ Typically accepts a position command signal​ (e.g., ±10V DC, 4-20mA) from the primary speed/load controller and a position feedback signal​ from the actuator-mounted LVDT/RVDT.
• Advanced Diagnostics:​ Continuously monitors key parameters such as coil current, feedback signal health, and tracking error. It can detect and report faults like open/short circuits, LVDT failure, or excessive deviation.
• Configurable Parameters:​ Allows tuning of servo loop gains (Proportional, Integral), null/bias adjustments, current limits, and response characteristics via configuration software to match the specific actuator dynamics.
• Status & Fault Indication:​ Equipped with LEDs to indicate power, run status, communication activity, and specific fault conditions.

3. Common Technical Specifications

• Part Number Context:​ The base number (5437) indicates the product family (servo/actuator drivers), and the suffix (523) specifies the exact hardware variant, which defines voltage ranges, connector types, and output drive capabilities.
• Command Input:​ Analog (±10V DC, 4-20mA) or digital (synchronous serial from a compatible Woodward controller).
• Feedback Input:​ AC-excited LVDT/RVDT (typical excitation: 2.5 — 5 Vrms, frequency: 2.5 — 10 kHz).
• Output Drive:​ Capable of driving typical servo valve coils (e.g., current output in the range of ±40 mA to ±300 mA, depending on the specific 5437 model and coil impedance).
• Power Supply:​ Requires DC power, commonly ±15 V DC for analog circuitry and +24 V DC for the output drive stage.
• Communication:​ Often includes a Woodward proprietary communication port​ (e.g., for Gov. Bus/NetBus) for configuration and diagnostics via Woodward Toolkit​ software.
• Physical Form:​ Typically a printed circuit board (PCB)​ module designed for mounting inside a Woodward control cabinet or a custom enclosure.

4. System Integration & Configuration

• Role in Control Architecture:​ It is the final control element driver​ in a cascade control loop:
  1. Primary Controller:​ Calculates the required fuel or air setpoint.
  2. Servo Driver (5437-523):​ Receives the setpoint as a command and drives the actuator to that exact position.
  3. Actuator & LVDT:​ The physical device and its position sensor complete the loop.
• Configuration Tool:​ Configured, tuned, and calibrated using Woodward Toolkit​ software connected via a service port or network.
• Calibration:​ A critical setup procedure involves calibrating the LVDT feedback span and offset to match the actuator’s mechanical stroke, ensuring commanded position equals actual position.

5. Typical Applications

• Diesel Engines:​ Controlling the fuel injection rack or actuator on engines for power generation, marine propulsion, or locomotives.
• Gas Engines:​ Positioning gas admission valves or throttle valves.
• Gas Turbines:​ Driving fuel metering valves, inlet guide vanes (IGVs), or bleed valves for performance and surge control.
• Steam Turbines:​ Governing steam inlet control valves.