Description
Input Signal: 4–20 mA DC (two-wire, loop-powered)
Output Signal: 3–15 psi (0.2–1.0 bar) pneumatic
Supply Voltage: 24 VDC nominal (operating range 18–32 VDC)
Supply Pressure: 80 psi (5.5 bar) regulated air supply required
Air Consumption: Low flow design, typically under 1 SCFM at full stroke
Accuracy: ±1% of full scale
Linearity: ±0.5% of full scale
Repeatability: ±0.25% of full scale
Deadband: Adjustable, typically less than 0.5%
Response Time: Less than 1 second to 90% of final position
Operating Temperature Range: -40°C to +85°C (-40°F to +185°F)
Storage Temperature Range: -50°C to +90°C (-58°F to +194°F)
Ambient Humidity: 5% to 95% non-condensing
Vibration Tolerance: Meets IEC 60068-2-6 standards
Ingress Protection: IP66 / IP67 rated enclosure (NEMA 4X compatible)
Housing Material: Cast aluminum alloy with epoxy-polyester powder coat finish
Internal Components: Stainless steel (316L) for wetted parts
Diaphragm Material: Nitrile rubber (NBR) / Fluoroelastomer (FKM) options available
Electrical Connectors: 1/2″ NPT conduit entries, DIN 43650 connector compatible
Structure: Compact modular housing with integrated I/P (current-to-pneumatic) converter and pneumatic relay
Mounting: Direct mount on actuator or wall/panel mount with bracket
Dimensions (approximate): 180 mm × 130 mm × 120 mm (L × W × H)
Weight: Approximately 2.5 kg (5.5 lbs)
Working Principle:
The 4–20 mA input current drives an internal torque motor that moves a flapper relative to a nozzle. This modulates backpressure in a pneumatic relay, which amplifies the signal to produce a proportional 3–15 psi output. The output pressure acts on a piston or diaphragm actuator to position the valve. Feedback from the valve stem position is compared to the input signal to achieve closed-loop proportional control.
Key Features:
- Two-wire loop-powered operation — no separate power supply required
- Fail-safe options available — air-to-open or air-to-close with spring return
- Adjustable zero and span — field calibration via potentiometers
- LED status indicators — power, signal, and fault diagnostics
- HART protocol compatible — digital communication for advanced diagnostics and configuration
- Intrinsically safe option available — for hazardous area classifications
Advantages:
- High precision and fast response for tight process control
- Robust construction suitable for harsh industrial environments
- Low air consumption reduces operating costs
- Simple installation with minimal wiring
- Proven reliability in continuous duty power generation service
Applicable Industries:
- Power Generation — gas turbine fuel control, steam turbine governing
- Oil & Gas — refinery process control, pipeline regulation
- Chemical / Petrochemical — flow and pressure regulation
- Pulp & Paper — steam and air damper control
- Water / Wastewater — valve position control in treatment plants
Compatible Actuator Types:
- Rotary actuators (quarter-turn valves, dampers)
- Linear actuators (globe valves, slide valves)
- Woodward EG, EH, EJ series actuators
Installation Requirements:
- Mount in a location protected from direct sunlight, rain, and excessive vibration
- Provide clean, dry, oil-free air supply at 80 psi (5.5 bar) with a filter-regulator
- Ensure proper electrical grounding per NEC / IEC standards
- Use shielded cable for signal wiring in high-EMI environments
- Verify supply voltage is within 18–32 VDC range before energizing
Usage Precautions:
- Do not exceed maximum supply pressure of 100 psi (6.9 bar)
- Do not operate without a filter on the air supply — contaminants will damage internal components
- Verify fail-safe direction (air-to-open vs air-to-close) matches process safety requirements before commissioning
- Perform zero and span calibration after installation and periodically during maintenance
- Replace diaphragm and seals according to scheduled maintenance intervals (typically every 2–3 years in harsh service)
- Do not disassemble in hazardous (classified) areas unless the unit is certified for that environment
Certifications:
- ATEX Zone 1 / Zone 2 (with intrinsic safety option)
- IECEx certified
- SIL 2 capable (with appropriate safety functions)
- UL / CSA listed
- CE marked
Documentation Reference:
- Woodward 5500 Series Installation & Operation Manual (Form 42607)
- Woodward 5501 Series Technical Data Sheet (Form 42512)




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