Samson Electropneumatic Valve Positioner 3725 3730-3
Product Overview
The Samson Electropneumatic Valve Positioners 3725 and 3730-3 are designed to provide precise and reliable positioning of pneumatic control valves in industrial process automation systems. These positioners convert electrical control signals into pneumatic output pressure, ensuring accurate valve stem movement and stable control performance.
The Samson 3725 is a robust electropneumatic positioner suitable for standard industrial applications, while the Samson 3730-3 is a smart digital valve positioner featuring advanced diagnostics, HART communication, and enhanced configuration capabilities.
Both models are widely used with Samson pneumatic diaphragm actuators and control valves, offering dependable operation in chemical, oil and gas, power generation, water treatment, and general industrial processes.
Key Features
- Electropneumatic valve positioner for pneumatic control valves
- High positioning accuracy and repeatability
- Supports 4–20 mA input signal
- Compatible with linear and rotary actuators
- NAMUR mounting interface for easy installation
- Stable performance under varying process conditions
- Low air consumption for efficient operation
- Rugged housing for industrial environments
- Optional digital communication and diagnostics on 3730-3
- Proven reliability with Samson control valve systems
Model Overview
Samson 3725
Electropneumatic valve positioner designed for conventional control applications, offering simple setup and stable performance.
Samson 3730-3
Digital smart valve positioner with microprocessor-based control, HART communication, advanced diagnostics, and flexible configuration options.
Technical Specifications
| Parameter |
Value |
| Positioner type |
Electropneumatic and digital valve positioner |
| Input signal |
4–20 mA DC |
| Communication |
HART available on 3730-3 |
| Valve compatibility |
Linear and rotary control valves |
| Actuator compatibility |
Single-acting pneumatic actuators
Double-acting pneumatic actuators |
| Air supply |
Clean and dry instrument air |
| Mounting |
NAMUR standard mounting |
| Accuracy |
High positioning accuracy with minimal hysteresis |
| Enclosure |
Industrial-grade housing suitable for field installation |
| Hazardous area approvals |
Available depending on model and configuration |
Applications
- Control valve automation in chemical and petrochemical plants
- Flow, pressure, and level control in oil and gas processing
- Steam and utility control systems in power generation
- Water and wastewater treatment facilities
- Industrial process automation and control loops
- Retrofit of existing pneumatic control valves
Benefits
- Ensures accurate and stable valve positioning
- Improves overall control loop performance
- Reduces maintenance through reliable design and diagnostics
- Supports both traditional and digital automation strategies
- Easy integration with Samson actuators and valves
- Suitable for harsh and continuous operating environments
How It Works
The Samson electropneumatic valve positioner receives a 4–20 mA electrical control signal from the control system. This signal is converted into a proportional pneumatic output pressure, which drives the actuator to position the valve accurately. The internal feedback mechanism continuously compares the actual valve position with the control signal to maintain precise control.
The 3730-3 digital model adds advanced diagnostics and communication functions for monitoring valve and actuator condition.
Installation Overview
- Mount the positioner on the actuator using the NAMUR interface
- Connect the instrument air supply and pneumatic tubing
- Wire the 4–20 mA input signal
- Perform calibration and functional testing
- Verify valve response under operating conditions
Frequently Asked Questions
What is the main difference between 3725 and 3730-3
The 3725 is a conventional electropneumatic positioner, while the 3730-3 is a digital smart positioner with diagnostics and HART communication.
Are these positioners compatible with Samson actuators
Yes, they are designed for seamless integration with Samson pneumatic actuators.
Can they be used in hazardous areas
Yes, certified versions are available depending on configuration.
Do they support rotary valves
Yes, both models can be used with linear and rotary valves using appropriate mounting kits.
Are they suitable for retrofit projects
Yes, they are commonly used to replace older analog positioners.
Related Products
- Samson 3277 Pneumatic Diaphragm Actuator
- Samson 3241 Globe Control Valve
- Samson 4763 Pneumatic Positioner
- Fisher DVC6200 Digital Valve Controller
- Masoneilan SVI2 Digital Valve Positioner
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