RTD Sensor Manufacturer in India – PT100 Resistance Temperature Detectors

Autologic Controls is an Ahmedabad-based RTD sensor manufacturer supplying a comprehensive range of 40+ Resistance Temperature Detectors (RTDs) for industrial, commercial, and process applications across India. Our RTD sensors — built on PT100, PT500, and PT1000 platinum elements — deliver the accuracy, repeatability, and long-term stability that process-critical temperature measurement demands.

From standard head-type PT100 sensors to specialized designs including flameproof RTDs for hazardous area installations, bearing temperature detectors for rotating machinery, autoclave RTDs for sterilization equipment, and duplex assemblies for redundant measurement — our product range is built to cover the full spectrum of temperature sensing requirements in one place.

All sensors are manufactured at our Ahmedabad facility in wire configurations of 2-wire, 3-wire, and 4-wire, with accuracy compliant with IEC 60751 Class A and Class B standards, and sheath materials in SS304, SS316, and Inconel to suit every process environment.

What Is an RTD Sensor? How Does It Work?

An RTD (Resistance Temperature Detector) is a temperature sensor that operates on the principle that the electrical resistance of certain metals changes predictably and proportionally with temperature. When temperature rises, resistance rises; when temperature falls, resistance falls. By measuring this resistance precisely, the exact temperature of the process can be determined.

The most widely used RTD element is platinum — which is why RTDs are most commonly known as PT100 sensors (from ‘Platinum’ and ‘100 ohms at 0°C’). Platinum is chosen because it has an extremely stable, linear, and reproducible resistance-temperature relationship across a wide range, making PT100 sensors the most accurate temperature sensors for industrial use in the -200°C to +600°C range.

RTDs are passive devices — they need an external current source to measure resistance. The instrument (temperature controller, transmitter, or PLC) supplies a small known current, measures the resulting voltage across the RTD element, calculates the resistance, and converts it to a temperature reading using the standard IEC 60751 platinum curve.

Pt100 vs Pt500 vs Pt1000 – What Is the Difference?

All three are platinum RTD elements but differ in their nominal resistance at 0°C. The choice affects accuracy, lead-resistance error, and instrument compatibility:

Autologic Controls manufactures PT100, PT500, and PT1000 elements. PT100 is the default for most industrial orders. Specify your required element type when requesting a quote.

2-Wire, 3-Wire and 4-Wire RTD – Which Configuration Do You Need?

The number of wires in an RTD sensor affects measurement accuracy and how the instrument compensates for lead wire resistance. This is one of the most common buyer questions:

Most industrial RTD orders use 3-wire configuration. 4-wire is specified for pharmaceutical validation, calibration standards, and precision process control.

RTD Accuracy Classes – Class A vs Class B (IEC 60751)

IEC 60751 defines two standard accuracy classes for platinum RTD elements:

Autologic Controls supplies both Class A and Class B RTDs. Specify your required class at the time of order. Class A sensors carry a modest price premium over Class B.

RTD Sensor – Full Technical Specifications

Browse Our RTD Range by Category

Our RTD Sensor Product Variants – Specialized Designs We Manufacture

With 40+ products across two subcategories, our RTD range covers standard configurations as well as highly specialized application-specific designs. Key variants include:

PT100 Head Type RTD Sensor

The standard industrial RTD — a platinum sensing element in a metal sheath with a terminal connection head for field wiring. Available in aluminum, cast iron, or stainless steel heads, with insertion lengths from 50mm to 1000mm+, and process connections in NPT, BSP, compression, or flange mount. This is the workhorse RTD for general temperature measurement in pipes, vessels, tanks, and ducts across any process industry.

Flameproof (FLP) Head RTD PT100 Sensor

Designed for temperature measurement in Zone 1 and Zone 2 hazardous areas — chemical plants, refineries, solvent manufacturing, paint plants, and gas handling facilities. The flameproof (Exd) enclosure is certified to prevent the transmission of any internal explosion to the surrounding atmosphere. Our FLP RTD sensors comply with IS/IEC Exd standards and are available in Group IIA/IIB/IIC classifications as required by your hazardous area classification report.

Bearing Temperature Sensor (BTD)

Specifically designed for monitoring the temperature of motor and generator bearings — a critical machine protection measurement. Bearing temperatures above set limits indicate lubrication failure, overloading, or mechanical wear before catastrophic damage occurs. Our bearing RTD sensors are constructed with a flat sensing tip for direct contact with the bearing surface, a flexible armoured lead, and PT100 duplex elements for redundancy. Available as surface-mount or push-in types depending on the bearing housing design.

Autoclave RTD Sensor

Designed for installation in autoclaves and steam sterilizers used in pharmaceutical manufacturing, hospital central sterile supply departments (CSSD), and food processing. These sensors must withstand repeated high-pressure steam cycles (typically 134°C at 3 bar), aggressive cleaning chemicals, and must be made from materials compliant with pharmaceutical and food-grade standards — SS316L with electropolished finish. Our autoclave RTD sensors are available with sanitary tri-clamp fittings or NPT threaded process connections.

Duplex RTD Sensor with Transition Joint (Pencil Type)

A duplex RTD contains two independent PT100 elements in a single sheath — providing redundant temperature measurement from one installation point. If one element fails or drifts outside tolerance, the second continues to provide valid readings without process interruption. The transition joint (pencil type) construction uses a mineral insulated cable section transitioning to a PVC or Teflon extension — providing flexibility for routing in tight spaces. Widely used in pharmaceutical batch reactors, power plant steam lines, and any critical measurement loop requiring a backup element.

L-Type RTD Sensor

An L-type (90° bend) RTD sensor is used where horizontal pipe or duct installations require the sensor probe to enter from the side with the lead exiting upward or in a different direction from the probe axis. The rigid L-bend is precision-formed to maintain accurate insertion depth. Available with all standard process connections and head types. Particularly common in compressed air lines, horizontal pipework, and installations where a straight probe assembly would create an obstruction.

Customize Pin Type RTD Sensor for Surface Measurement

Surface-mount RTD sensors measure the temperature of a solid surface rather than an immersion in a fluid. The pin-type design uses a flat-bottom sensing tip with a spring-loaded mechanism to maintain consistent contact pressure with the surface — essential for accurate surface temperature measurement. Applications include roll temperature measurement in paper mills and printing machinery, die temperature monitoring in moulding equipment, extruder barrel surface temperature, and pipe surface temperature in insulated lines.

RTD Sensor vs Thermocouple – When to Choose Which

Rule of thumb: Use RTD (PT100) when accuracy and stability are the priority and temperature is below 600°C. Use a thermocouple when temperature exceeds 600°C or when fast response and cost are more important than ultimate precision.

Industries and Applications We Serve

• Pharmaceutical Manufacturing: Autoclave sterilizers, bioreactor vessels, clean room HVAC, WFI (water for injection) systems — PT100 Class A with SS316L for GMP compliance.
• Chemical and Petrochemical: Reactor jacketing, distillation columns, heat exchangers — FLP-rated heads for Zone 1/2 areas, SS316 sheath for corrosive media.
• Food and Beverage: Pasteurizers, fermentation tanks, storage silos, CIP lines — hygienic SS316L with sanitary fittings, Class A accuracy for product quality control.
• Power Plants: Bearing temperature monitoring on turbines and generators, winding temperature detectors — duplex RTDs for redundancy in critical assets.
• HVAC and Building Automation: Duct air temperature, chilled water circuits, air handling units — PT1000 or PT100 with compact head type, 3-wire configuration.
• Plastics and Rubber: Extruder barrel temperature, die temperature, hot plate monitoring — pin-type surface RTDs and bayonet assemblies.
• Textile Industry: Stenter machine temperature, dryer rolls, dyeing machine bath temperature — high-humidity environments with IP65+ sealing.
• Oil and Gas: FLP/ATEX-rated RTDs for wellhead, separator, and metering skid applications in hazardous classified areas.
• Automotive Manufacturing: Paint oven temperature, body-in-white process control, test cell engine coolant temperature.
• Research and Calibration Labs: 4-wire PT100 Class A or 1/3 DIN accuracy for calibration baths, environmental chambers, and metrology applications.

Why Choose Autologic Controls for RTD Sensors?

• 40+ Variants in One Range: From standard head-type PT100 to FLP, bearing, autoclave, duplex, L-type, and surface-mount — more specialist configurations than most Ahmedabad-based suppliers.
• Full Specification Range: PT100/PT500/PT1000 × 2-wire/3-wire/4-wire × Class A/Class B × SS316/Inconel sheath × all process connections — configured to your exact requirement.
• Ahmedabad Manufacturing: Locally manufactured in Gujarat — competitive pricing, faster lead times for domestic customers, and accessible technical support.
• Complete Temperature Sensing Ecosystem: We also manufacture thermocouples, thermowells, NTC sensors, compensating cables, and temperature controllers — one supplier for your complete temperature measurement infrastructure.
• Custom Design Accepted: Non-standard lengths, special materials, OEM configurations and drawings accepted. Share your application datasheet and we will engineer to it.
• Documentation: Material test reports, calibration certificates, and compliance documentation available on request — essential for pharma and food industry audits.