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Brand: Samson
Samson 4747 Ex d Limit Switch for Pneumatic Actuators
Description
Samson 4747 Ex d limit switch for hazardous-area actuators
The Samson 4747 is a limit switch with inductive or electric limit contacts, built for hazardous areas in either flameproof (Ex d) or intrinsically safe (Ex ia) type of protection. It is made for attachment to pneumatic linear and rotary actuators, including rotary actuators with the VDI/VDE 3845 interface, and it issues an electric signal when valve travel passes an adjusted limit. The signal can switch control circuits, drive visual or audible alarms or feed a central control system. Seven Star LLC supplies the Samson 4747 in Oman and the GCC as an independent supplier in Muscat.
The enclosure is rugged and corrosion-resistant with degree of protection IP66, and the permissible ambient temperature reaches –40 to +80 °C depending on the contact type and approval.
Technical specifications of the 4747
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Samson Type 4747 |
| Limit contacts | Maximum two, continuously adjustable between 0 and 100° |
| Inductive version | Proximity sensor NCB2-V3-NO, NAMUR NC contact, switching amplifier according to EN 60947-5-6; ambient –25 to +80 °C |
| Electric version | Changeover contact (SPDT), silver or gold plated; 250 V AC / 10 A; two contacts; ambient –40 to +80 °C |
| Degree of protection | IP66 |
| Electrical connection | M20x1.5 or ½ NPT cable gland to terminals |
| Enclosure and cover | Aluminum, powder coated gray beige RAL 1019, or stainless steel 1.4409 |
| External parts | Stainless steel 1.4301 / 1.4310 / 1.4409 |
| Ex ia circuit values (inductive 4747-11×01) | Ui 16 V; Ii 25 mA or 52 mA; Pi 64 mW or 169 mW; Ci 100 nF; Li 100 µH |
| Weight | Approx. 0.65 kg |
| Mounting | Kits for linear actuators per IEC 60534-6-1, rotary actuators per VDI/VDE 3845, or Samson direct attachment |
Explosion protection options of the 4747
The first group of digits in the article code selects the type of protection. The datasheet lists the following families:
| Type of protection | Datasheet listing |
|---|---|
| Intrinsic safety (Ex ia) | ATEX II 2G Ex ia IIC T6 Gb with dust protection II 2D Ex ia IIIC T85 °C Db IP66; EAC Ex and TR CMU 1055 equivalents |
| Flameproof (Ex d) | ATEX II 2G Ex db IIC T6…T4 Gb and II 2D Ex tb IIIC T80 °C Db; IECEx, CCC Ex, NEPSI, EAC Ex and TR CMU 1055 equivalents |
| North America | FM: XP/I/1/ABCD/T6, Type 4X, IP66; CSA: Class I Div 1 and 2, Class II, Class III, Type 4X, IP66 |
| Zone 2 / non-sparking | ATEX II 3G Ex ic IIC T6 Gc, II 3G Ex nAc II T6 Gc and II 3D Ex tc IIIC T85 °C Dc IP66 |
| Without | Non-hazardous areas only |
The listed approvals apply to specific sub-types. As the datasheet itself notes, the technical data for explosion-protected devices may be limited further by the test certificate, so the certificate for the exact code should be checked before use in a classified area.
How the 4747 detects the end positions
A follower pin connects the shaft of the limit switch to the actuator. On the inductive version, adjustable metal tags on the shaft move in and out of the field of the proximity sensors, changing their output impedance. On the electric version, adjustable cam disks press a roller on a microswitch lever. In both cases the switching point is set between 0 and 100° at an adjustment screw, so the contacts can indicate the two end positions or an intermediate position. Most plants use the contacts for open and closed feedback to the DCS or safety system.
Decoding the 4747 article code
After the type of protection, the code selects the limit contact, the number of contacts, the electrical thread and the temperature range:
| Position | Available option |
|---|---|
| Limit contact | Inductive NCB2-V3-NO (–25 to +80 °C); microswitches with silver contacts or gold contacts (–40 to +80 °C) |
| Number of contacts | 1 or 2 |
| Switching angle | Less than 100° adjustable |
| Electrical connection | M20x1.5 or ½ NPT |
| Ambient temperature | –25 to +80 °C; –40 to +80 °C; –25 to +70 °C (maximum +65 °C in T6) |
| Material | Aluminum or stainless steel |
Selection and ordering checklist for the 4747
- Area classification and the required type of protection and approval.
- Contact type: inductive for amplifier circuits, microswitch for direct switching; silver or gold.
- One or two limit contacts.
- Cable entry: M20x1.5 or ½ NPT.
- Enclosure: aluminum for general duty, stainless steel for marine and corrosive areas.
- Ambient temperature range, noting the reduced limit in T6.
- Actuator type: linear (IEC 60534-6-1) or rotary (VDI/VDE 3845), with fixing level and light or heavy-duty bracket.
Installation and commissioning of the 4747
Choose the mounting kit that matches the actuator interface: the datasheet shows attachment to VDI/VDE 3845 rotary actuators at fixing levels 1 and 2, direct attachment to linear actuators and attachment to a NAMUR rib. Align the follower pin with the actuator shaft, set the contacts with the valve at each end of travel and verify the switching signals at the control system before sealing the cover. For flameproof versions use cable glands and plugs certified for the same type of protection and do not open the enclosure while energized in the hazardous area. Close all unused entries to retain the IP66 rating, which matters in dusty and humid sites.
Typical applications in Oman and the GCC
Flameproof and intrinsically safe limit switches are used on quarter-turn ball and butterfly valves with pneumatic actuators in oil and gas gathering, tank farms, loading terminals, refineries and petrochemical units. The IP66 enclosure and stainless steel option suit coastal and offshore salt-laden air, and the +80 °C ambient rating covers exposed installations in Gulf summers, while radiant heat near hot lines should still be checked against the temperature class.
Information to send with an RFQ for the 4747
- Complete 4747 code from the existing nameplate, if replacing a unit.
- Required approval and area classification (zone, gas group, temperature class).
- Actuator make, model and mounting interface.
- Contact type, number of contacts and cable entry.
- Quantity and delivery location.
Documents and quotation
The Samson Type 4747 datasheet (T 4747 EN) is attached on this page and contains the article code, dimensions and approval summary.
Send us the code and project details and Seven Star LLC will confirm availability and prepare a quotation for Oman and the GCC.
Other Models in the Samson Limit Switches Range
Seven Star LLC supplies models from the Samson Limit Switches range in Oman and the GCC. Compare the related models below and request a quote for the one that matches your application.
| Model | Category | |
|---|---|---|
| Samson 4740 Electric Limit Switch with Optional Solenoid | Valve Positioners | View details |
| Samson 4747 Ex d Limit Switch for Pneumatic Actuators | Valve Positioners | You are viewing this model |
Datasheets & Documents
- Datasheet Samson 4747 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 4747 Ex d Limit Switch for Pneumatic
Answers from our engineering team on installation, compatibility and integration.
01What does the Samson 4747 do?
It is a limit switch for pneumatic linear and rotary actuators that sends an electric signal when valve travel passes an adjusted limit.
02Which types of protection exist?
Intrinsic safety (Ex ia), flameproof enclosure (Ex d) and Zone 2 versions, plus FM and CSA approvals for North America, depending on the article code.
03What is the degree of protection and temperature range?
IP66 with ambient temperature up to +80 °C; the lower limit is –25 or –40 °C depending on the contact type and code.
04How many limit contacts can it have?
A maximum of two, each continuously adjustable between 0 and 100°. They can be inductive proximity sensors or electric microswitches.
05How is it mounted?
With kits for IEC 60534-6-1 linear actuators, VDI/VDE 3845 rotary actuators or Samson direct attachment.
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