The Plug-in Resistance Temperature Detector (RTD) series manufactured by Reckmann GmbH (Germany) provides specialized industrial temperature measurement solutions engineered for direct insertion into process pipelines or installation within separate thermowells without fixed threaded process connections. This unthreaded plug-in architecture allows maintenance technicians and system engineers to flexibly calibrate the immersion depth on-site using sliding compression fittings or mounting flanges, ensuring that the sensor's active tip is precisely aligned with the core fluid flow path for maximum measurement fidelity.

The series is mechanically standardized into two fundamental configurations compliant with DIN 43772:
1. Plug-in RTD Model 2: Engineered with a uniform straight protective sheath (Straight protection tube - Form 2). This serves as a versatile, heavy-duty, and economical temperature sensing solution for fluid transport pipelines with moderate flow velocities or bulk process storage vessels. Its robust, thick-walled construction delivers high structural integrity, exceptional static pressure containment, and superior resistance against mechanical bending caused by persistent fluid momentum.
2. Plug-in RTD Model 3: Specifically engineered with a stepped-down / tapered tip geometry (Form 3). By reducing the sheath diameter at the measurement tip where the Pt100 platinum resistor is embedded, thermal mass is drastically decreased. This geometric optimization leads to extraordinarily fast response kinetics (drastically reduced t0.5 and t0.9 response times), making Model 3 the prime choice for applications with rapid thermal fluctuations, smaller pipe diameters, or high-velocity liquid flows where vortex-induced shedding and mechanical vibrations must be minimized.

Both models incorporate high-density Magnesium Oxide (MgO) mineral-insulated sensing inserts encapsulated within premium corrosion-resistant stainless steel alloys (AISI 316Ti / 1.4571 or AISI 316L / 1.4404). This configuration ensures maximum operational immunity against mechanical shock, prevents thermal fatigue, and accommodates a wide temperature envelope from cryogenic ranges to elevated process heat. The assemblies are terminated with standardized industrial Form B cast aluminum connection heads (rated IP65/IP66) with sufficient internal volume to host programmable head-mounted temperature transmitters (4-20mA / HART / Modbus protocols), facilitating reliable long-distance telemetry to central PLC/SCADA architectures.

• Manufacturer: Reckmann GmbH
• Country of Origin: Germany
• Product Models Covered:
  - Plug-in RTD Model 2 (Uniform straight cylindrical protection tube per DIN 43772 Form 2)
  - Plug-in RTD Model 3 (Stepped-down / tapered tip protection tube per DIN 43772 Form 3 for ultra-fast response)
• Sensing Resistor: High-purity Platinum RTD Pt100 or Pt1000 per DIN EN 60751
• Element Configuration: Simplex (1xPt100) or Duplex (2xPt100 for safety redundancy)
• Wiring Configurations: 2-wire, 3-wire, or 4-wire (4-wire circuit entirely eliminates lead resistance inaccuracies)
• Tolerance Accuracy Class: Class B (±0.3°C at 0°C), Class A (±0.15°C at 0°C), or ultra-precise 1/3 DIN
• Operating Temperature Range: -50°C to +400°C (Extended from -200°C up to +600°C with mineral-insulated cores)
• Outer Sheath Diameters:
  - Model 2: Uniform Ø6 mm, Ø8 mm, Ø9 mm, Ø11 mm, or Ø12 mm
  - Model 3: Main stem Ø9 mm or Ø11 mm, stepped down to Ø6 mm at the measuring tip
• Standard Immersion Lengths: 100 mm, 160 mm, 250 mm, 400 mm (or custom fabricated to exact specifications)
• Mounting Methods: Sliding compression fittings (G1/2", 1/2" NPT male threads) or adjustable clamping flanges
• Wetted Sheath Material: Stainless steel AISI 316Ti (1.4571) or AISI 316L (1.4404) for optimal acid/chemical resistance
• Connection Head: Standard industrial Form B cast aluminum terminal head (Optional Form J or Form BUZ)
• Ingress Protection Rating: IP65 minimum (up to IP66 with properly torqued M20x1.5 cable glands)
• Transmitter Integration: Compatible with head-mounted puck transmitters providing 4-20mA analog output or HART communication