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Brand: Samson
Samson 3730-4 PROFIBUS-PA Electropneumatic Positioner
Description
Samson 3730-4 PROFIBUS-PA electropneumatic positioner
The Samson 3730-4 is a smart electropneumatic positioner for pneumatic control valves that talks to the control system over PROFIBUS-PA. It sits on the valve actuator, compares the set point arriving on the fieldbus with the measured stroke or opening angle, and drives the actuator with the air pressure needed to close the gap. The device is bus-powered according to IEC 61158-2, so one twisted pair carries both power and data, and no separate 4-20 mA loop is needed.
The datasheet T 8384-4 covers valve travel from 3.6 to 300 mm and rotary opening angles from 24 to 100°. Seven Star LLC supplies the Samson 3730-4 in Oman and the GCC as an independent supplier in Muscat, usually for plants that already run PROFIBUS-PA segments and want valve diagnostics on the same network.
Decoding the 3730-4 designation
In the Series 3730 the digit after the hyphen names the communication variant. The datasheet lists the 3730-4 as the PROFIBUS-PA version, while the sibling 3730-3 is the HART version and 3730-5 is the FOUNDATION fieldbus version. The 3730-4 article code then adds explosion-protection, limit-switch, solenoid-valve and external-sensor options, so two positioners called 3730-4 can differ considerably.
3730-4 technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Samson / 3730-4 (Series 3730, datasheet T 8384-4) |
| Communication | PROFIBUS-PA per IEC 61158 and IEC 61784, PA Profile 3.01 certified, meets Profile 3.02; FDT/DTM 1.2 file available |
| Power supply | Bus-powered, 9 to 32 V DC; maximum operating current 15 mA; no additional current in case of error |
| Valve travel (adjustable) | 3.6 to 30 mm on Type 3277 direct attachment; 3.6 to 300 mm with NAMUR or VDI/VDE 3847 attachment |
| Rotary actuators | 24 to 100° opening angle (VDI/VDE 3845) |
| Supply air | 1.4 to 7 bar (20 to 105 psi), air quality per ISO 8573-1; output signal pressure limitable to 1.4, 2.4 or 3.7 bar |
| Characteristics | Linear, equal percentage, reverse equal percentage, user-defined, plus butterfly, rotary plug and segmented ball curves |
| Accuracy figures | Characteristic deviation ≤ 1 %, hysteresis ≤ 0.3 %, sensitivity ≤ 0.1 % |
| Air output capacity | Fill 8.5 mn³/h at 6 bar differential; vent 14.0 mn³/h at 6 bar differential |
| Ambient temperature | –20 to +80 °C; –45 to +80 °C with metal cable gland |
| Enclosure | IP 66 / NEMA 4X; die-cast aluminum housing, optional stainless steel 1.4408; approx. 1.0 kg |
| Safety use | Emergency venting with the optional solenoid valve usable up to SIL 2 (single) and SIL 3 (redundant) when IEC 61511 requirements are met |
How the 3730-4 positions the valve
A travel sensor without gears reports the valve position, an A/D converter feeds a microcontroller, and a PD control algorithm compares position with the fieldbus set point. The result drives an i/p converter followed by an air capacity booster, which fills or vents the actuator. A fixed flow regulator keeps a small constant air purge through the housing, which cools and cleans the interior; the pressure regulator keeps the i/p module at constant upstream pressure so supply fluctuations have little effect.
Operation on site uses a single rotary pushbutton. All parameters sit on one menu level, the LCD can be turned 180°, and an automatic start-up (INIT) finds the stroke and tunes the loop. The EXPERTplus diagnostics are integrated, and status alarms follow NAMUR NE 107. A binary input for DC voltage signals is standard, so a process switch can report over PROFIBUS-PA.
Where the 3730-4 fits and related Samson positioners
The 3730-4 mounts directly on the Type 3277 pneumatic actuator, on NAMUR ribs and rod-type yokes per IEC 60534-6-1, on VDI/VDE 3847 interfaces, and on rotary actuators through VDI/VDE 3845 kits, including the Type 3278 rotary actuator. It can control Samson valves such as Type 3241 and 3251 as well as third-party valves with standard attachment. Related parts are the 3730-3 (HART), 3730-5 (FOUNDATION fieldbus), 3731-3 (Ex d, HART) and the TROVIS 3793.
For double-acting actuators a pneumatic reversing amplifier is available in the ordering text, so the same positioner can serve both spring-return and double-acting rotary designs.
3730-4 selection and ordering checklist
- Confirm the control system supports PROFIBUS-PA with a DP/PA coupler and that segment power and device count allow another 15 mA load.
- State the actuator: Type 3277 with surface area 175 to 750 cm², NAMUR rib, VDI/VDE 3847 or a rotary actuator under VDI/VDE 3845, with rated travel or angle.
- Select the pneumatic connection: ISO 228/1 G ¼ or ¼-18 NPT connecting rail, with or without a pressure gauge up to 6 bar.
- Specify the explosion-protection scheme needed (ATEX, IECEx, CSA, FM and other certificates are listed against the article code).
- Choose optional inductive limit contact, solenoid valve for emergency venting, binary input 2, external position sensor and housing material.
Installation, commissioning and maintenance of the 3730-4
Mount the 3730-4 in any position except suspended. Connect the bus cable to the screw terminals (0.2 to 2.5 mm²) through the M20 x 1.5 gland, set the DIP switch for air-to-open or air-to-close, and start initialization. Because the supply air must meet ISO 8573-1 classes, install a filter regulator upstream; a dew point at least 10 K below the lowest expected ambient is specified.
During commissioning the TROVIS-VIEW software with the 3730-4 database module can be linked through the local SSP interface and serial adapter, and the DTM can be loaded into an FDT frame or an EDD into a PDM tool. In service, the permanent storage of parameters keeps settings after a power loss, and the EXPERTplus diagnostics help plan valve maintenance rather than waiting for a failure.
Typical applications of the 3730-4 in Oman and the GCC
The 3730-4 suits process plants built around PROFIBUS-PA instrumentation: chemical and petrochemical units, gas processing trains, power-plant water and steam systems and desalination plants where control valves are numerous. The wide ambient range, the –45 °C to +80 °C limit and IP 66 housing handle outdoor valves in dust and heat, while the sealed design resists humid coastal air. Where emergency venting is needed, the solenoid option provides a path for safety loops.
Information to send with an RFQ for the 3730-4
- Complete article code or the options required (explosion protection, limit switch, solenoid, external sensor).
- Valve and actuator model, stem travel or rotary angle, and spring or double-acting action.
- Fieldbus architecture, coupler type and any DTM or EDD requirement.
- Supply air pressure and the project approval needs.
- Quantity and delivery location in Oman or the GCC.
Documents and quotation
The Samson datasheet T 8384-4 for the 3730-4 is attached on this page and lists the technical data, explosion-protection certificates and ordering text.
Send us the full article code or the valve data, and Seven Star LLC will prepare a quotation for the Samson 3730-4 positioner.
Datasheets & Documents
- Datasheet Samson 3730-4 Datasheet Download
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About brand
SAMSON is a German manufacturer of control valves, actuators, positioners and self-operated regulators. Hermann Sandvoss founded the company in Düsseldorf on 1 April 1907, and its first important product was a thermostatic valve that controlled temperature without external power. After moves to Mannheim, SAMSON settled in Frankfurt am Main in 1916, where SAMSON AG is still headquartered.
Seven Star LLC supplies Samson control valves, pneumatic actuators and positioners to process plants in Oman, including the types listed on this page and their replacement units.
Samson company profile
| Founded | 1 April 1907, Düsseldorf, by Hermann Sandvoss, as VULCAN Technische Apparate Baugesellschaft; products sold under the SAMSON name |
|---|---|
| Headquarters | Frankfurt am Main, Germany, since 1916 |
| Legal form | SAMSON AG |
| First product | A self-operated thermostatic valve |
| Group brands | SAMSON together with PFEIFFER, LEUSCH, VETEC and AIR TORQUE |
| Product families | Globe valves such as Type 3241, rotary and butterfly valves, 3271 and 3277 pneumatic actuators, 3730 and 3731 positioners, self-operated pressure and temperature regulators |
Milestones
- 1907: Hermann Sandvoss founds the company in Düsseldorf.
- 1909: It is re-established as SAMSON Apparatebau GmbH.
- 1916: After a period in Mannheim, the company moves to Frankfurt am Main.
- 1975: The name becomes SAMSON Mess- und Regeltechnik.
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.
Among 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.
Samson products we list
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
We check the code against Samson documentation and provide the manufacturer's data sheet on request.
Facts checked against SAMSON's corporate chronicle and press material, October 2026.
Browse Samson products by category: Control Valves, Valve Positioner, Valve Actuator.
FAQ
Questions about the Samson 3730-4 PROFIBUS-PA Electropneumatic
Answers from our engineering team on installation, compatibility and integration.
01What fieldbus does the Samson 3730-4 use?
It uses PROFIBUS-PA according to IEC 61158 and IEC 61784 and is powered over the bus at 9 to 32 V DC. A certified DTM file is available for FDT 1.2 frames.
02What valve travel can the 3730-4 handle?
Valve travel is 3.6 to 300 mm on linear actuators, with 3.6 to 30 mm for direct attachment to the Type 3277 actuator. On rotary valves the opening angle is 24 to 100°.
03Can the 3730-4 be used in safety loops?
With the optional solenoid valve for emergency venting at 0 V set point, the datasheet allows use up to SIL 2 as a single device and SIL 3 in a redundant arrangement, observing IEC 61511.
04How does the 3730-4 differ from the 3730-3?
The 3730-3 communicates over HART with a 4-20 mA loop, while the 3730-4 is bus-powered on PROFIBUS-PA. The pneumatic section and the mounting options follow the same Series 3730 design.
05What supply air does the 3730-4 need?
Supply air must be 1.4 to 7 bar (20 to 105 psi) and meet the ISO 8573-1 classes for particles, oil and water. The output pressure can be limited to 1.4, 2.4 or 3.7 bar in software.
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