SAMSON TROVIS 3730-1 Electropneumatic Positioner
Overview
The SAMSON TROVIS 3730-1 is an electropneumatic positioner for single-acting pneumatic globe and rotary control valves. It accepts a 4 to 20 mA set point, measures the valve travel or opening angle, and outputs the signal pressure the actuator needs to hold the commanded position. As the entry model of the TROVIS 3730 generation, it offers self-calibrating start-up, non-contact position sensing and a robust die-cast aluminum housing, without HART communication, which makes it a straightforward replacement for analog positioners on throttling valves.
Seven Star LLC supplies the SAMSON TROVIS 3730-1 to operators and contractors across the Sultanate of Oman and the wider GCC. As a trusted supplier with engineering support in Muscat, we help customers choose the right attachment, housing material and options such as position transmitters and limit switches. Each order is checked against the actuator data sheet so that the mounting kit, lever length and cable entries are correct on arrival.
Operating Principle
The SAMSON TROVIS 3730-1 consists of a non-contact travel sensor system, a pneumatic section and electronics with a microcontroller. The valve position is transmitted as linear travel or an angle of rotation to the pick-up lever, then to the travel sensor and on to the microcontroller. A PID algorithm compares the measured position with the 4 to 20 mA signal from the control system after it has passed the A/D converter.
When a set point deviation occurs, the activation of the i/p module is changed, and the downstream air booster pressurizes or vents the actuator. The closure member, for example the plug, then moves to the position defined by the set point. A pressure reducer stabilizes the supply to the pneumatic section, so changes in supply air pressure have no influence on the control result. Steady-state air consumption is about 65 ln/h, independent of supply pressure.
Engineering Design of the SAMSON TROVIS 3730-1
The housing and cover of the SAMSON TROVIS 3730-1 are die-cast aluminum EN AC-AlSi12(Fe) with chromate and powder coating, or stainless steel 1.4408 as a special version. The window is Makrolon, other external parts are stainless steel 1.4571 and 1.4301, and the unit weighs about 1.0 kg in aluminum or 2.2 kg in stainless steel. Protection is IP66/NEMA 4X, and the low-temperature version with metal cable glands operates down to –55 °C.
The positioner attaches to all common actuators: SAMSON direct attachment to the Type 3277, the NAMUR rib, rod-type yokes according to IEC 60534-6-1, the VDI/VDE 3847 interface and rotary actuators according to VDI/VDE 3845. Electrical connection is made through an M20x1.5 cable gland with a second threaded entry available, and screw terminals take 0.2 to 2.5 mm² wires. Operation uses a rotary pushbutton for menu navigation, and configuration from a computer is possible through the SSP interface with TROVIS-VIEW software.
Key Features
The SAMSON TROVIS 3730-1 brings the following features to standard control loops:
- Non-contact position sensing for long service life without wearing parts in the travel pick-up.
- Simple one-knob, menu-driven operation with an LCD whose reading direction can be selected.
- Variable automatic start-up that adapts the positioner to the valve and actuator.
- Two-wire connection with a small electrical load of about 315 ohms.
- Split-range operation using 4 to 11.9 mA and 12.1 to 20 mA signal ranges.
- Activatable tight-closing function and continuous zero monitoring.
- Optional position transmitter, software limit switches (NAMUR or PLC) and inductive limit switches.
- All parameters saved in non-volatile EEPROM to protect settings against power failure.
Industrial Applications
The SAMSON TROVIS 3730-1 suits throttling valves in utilities, water treatment, HVAC, district cooling and general process plants where a dependable 4 to 20 mA positioner is required and digital communication is not. Typical examples are steam pressure reduction, cooling water temperature control, tank level control and dosing valves in desalination and wastewater facilities. Its resistance to vibration and bumps, tested according to DIN EN 60068, also suits skid-mounted packages, pump stations and compressor stations where valves are exposed to continuous mechanical stress.
In oil and gas and petrochemical plants, intrinsically safe versions of the SAMSON TROVIS 3730-1 can be used on auxiliary and utility valves inside hazardous areas. Where HART diagnostics are needed, the HART version TROVIS 3730-3 is the alternative. Seven Star LLC helps customers in Muscat, Sohar and Salalah decide between the two and supplies the matching mounting kits.
Technical Specifications
The SAMSON TROVIS 3730-1 data below is taken from SAMSON data sheet T 8484-1 EN.
| Parameter | Specification |
|---|---|
| Model | SAMSON TROVIS 3730-1 Electropneumatic Positioner |
| Valve travel | 3.5 to 30 mm (Type 3277); 3.5 to 300 mm (IEC 60534-6, VDI/VDE 3847) |
| Opening angle | 24 to 100° (rotary actuators) |
| Set point | 4 to 20 mA, two-wire, reverse polarity protection; split range possible |
| Minimum current | 3.6 mA for display, 3.8 mA for operation |
| Load impedance | ≤6.6 V (330 Ω at 20 mA); Ex versions ≤7.3 V (365 Ω) |
| Supply air | 1.4 to 7 bar (20 to 105 psi), quality to ISO 8573-1 |
| Signal pressure | 0 bar up to supply pressure, can be limited to 2.4 bar ±0.2 bar |
| Hysteresis / sensitivity | ≤0.3 % / ≤0.1 % |
| Characteristics | Linear, equal percentage, reverse equal percentage, butterfly, rotary plug, segmented ball |
| Air consumption (steady state) | Approx. 65 ln/h |
| Air output (Δp 6 bar) | Supply 8.5 m³n/h; exhaust 14.0 m³n/h |
| Operating temperature | –20 to +85 °C; –40 °C with metal glands; –55 °C low-temperature version |
| Degree of protection | IP66 / NEMA 4X |
| Housing | Die-cast aluminum (approx. 1.0 kg) or stainless steel 1.4408 (approx. 2.2 kg) |
How to Order
To receive a formal RFQ response for the SAMSON TROVIS 3730-1, send Seven Star LLC your actuator type, travel or rotation angle, hazardous-area classification and required options. Our instrumentation division in Muscat provides the technical datasheet for download, confirms availability and lead time and can combine the positioner with the SAMSON Type 3271 diaphragm actuator and the SAMSON Type 3241 globe valve. If HART is required, ask about the Samson 3730-3 HART smart positioner. We deliver throughout Oman and the GCC.
- Datasheet SAMSON TROVIS 3730-1 Electropneumatic Positioner Datasheet (T 8484-1 EN) Download
Samson valve, actuator and positioner types
Samson builds a control valve from modules. The Type 3241 globe valve is the general-service body of Series 240, and the Type 3251 is the Series 250 body for higher pressure ratings. Either one is combined with a Type 3271 pneumatic diaphragm actuator or a Type 3277, whose yoke allows the positioner to be attached directly with a concealed travel linkage. The positioners listed are the Type 3725 and the Type 3730 family: the 3730-1 as the basic electropneumatic version, sold in its current generation as TROVIS 3730-1, and the 3730-3 with HART communication and valve diagnostics. Samson also makes PROFIBUS PA and FOUNDATION fieldbus variants in the same family, plus self-operated pressure and temperature regulators.Where Samson valves are used
Samson control valves throttle steam, gas and liquids in chemical and petrochemical units, refineries, gas processing, power stations, water and desalination plants, and food production. Many reach site as part of a skid or package, so the plant instrument team often meets them first when a positioner or actuator needs replacing. We supply these items to end users and contractors throughout the GCC.Ordering Samson parts: what we need
Every Samson device has a nameplate with the type, a configuration ID (Var-ID) and a serial number. A photo of that plate is the surest route to an exact match. Without it, please send:- Valve: type, DN or NPS, pressure rating, body and trim material, Kvs or Cv, plug and seat style, packing and bonnet type
- Actuator: type, effective area in cm², bench range, fail action and travel
- Positioner: full type code including Ex protection, communication and options such as limit switches or position transmitter
Browse Samson products by category: Control Valves, Valve Positioner, Valve Actuator.
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