Simple, Robust Infrared Temperature Sensor with Analogue Output


  • Choice of temperature ranges from -20°C to 500°C
  • Durable, robust stainless steel 316 housing
  • Fixed emissivity setting: 0.95
  • 4-20 mA, Type K or J thermocouple, or 0-50 mV output options
  • Fast response with high stability
  • Sealed to IP65
  • Measures non-reflective non-metals, or painted metal surfaces
  • Not designed or approved for fever detection

General Specifications

Temperature Range
-20°C to 100°C (LT models)
0°C to 250°C (MT models)
0°C to 500°C (HT models)
Choice of optics for small or large targets at short or long distances - see Field of View Diagrams
Output (Measured Temperature)
Two-wire 4-20 mA (-0 models)
0-50 mV (-1 models)
Type J Thermocouple (-3 models)
Type K Thermocouple (-4 models)
Output (Sensor Body Temperature)
4-20 mA on power loop (models with output options 1 to 4 only)
±1% of reading or ±1ºC, whichever is greater
± 0.5% of reading or ± 0.5ºC, whichever is greater
Fixed at 0.95
Response Time, t90
240 ms (90% response)
Spectral Range
8 to 14 μm
Supply Voltage
24 V DC (28 V DC max.)
Min. Sensor Voltage
6 V DC
Max. Loop Impedance
900 Ω ( 4-20 mA output)
Output Impedance
56 Ω (voltage/thermocouple output)

Field of View Diagrams

Please note: The given measured spot size contains 90% of the energy detected by the sensor. We normally recommend the target is at least twice as large as the given measured spot for maximum accuracy. Sensors may be used at longer distances than the above diagrams show. There is no maximum measurement distance in clean air; this is because the PyroCouple detects only the wavelengths of infrared radiation that are not absorbed by the atmosphere.

Mechanical Specifications

Stainless Steel
18 mm diameter x 103 mm long
Thread Mounting
M16 x 1 mm pitch
Cable Length
1m (longer lengths available to order)
Weight with Cable
95 g

Environmental Specifications

Environmental Rating
Ambient Temperature Range
0ºC to 70ºC
Relative Humidity
95% max. non-condensing

Electromagnetic Compatibility Standards

EN61326-1, EN61326-2-3 (Electrical Equipment for Measurement, Control and Laboratory Use – EMC Requirements – Industrial)

The PyroCouple is an ideal general-purpose sensor for a huge range of applications. For example, some typical uses include:

Typical Applications

For food temperature measurement, a fixed-emissivity sensor such as the PyroCouple is usually suitable. A range of controllers and indicators is also available. A famous manufacturer uses the PyroCouple to measure chocolate temperature before the mould as it is heated in temperature controlled "kettles", and the temperature of toffee webs as they leave cooling drums.
Measuring tarmac road surface temperature when paving and in infrared pothole repair. Asphalt temperature measurement after heating and in discharge chutes
Temperature and moisture monitoring and control in corrugated board manufacturing, paper drying and condition monitoring
Thermoforming temperature control and monitoring
Power industry
Monitoring the temperature of painted surfaces in switchgear
Microwave dryers
In food, paper, pharmaceutical and textile industries, among others, infrared temperature sensors can be positioned outside the microwave field and aimed at the object being dried
Infrared curing of paint and adhesives
If the emissivity of the target is high, the reflection of the infrared curing heater does not significantly influence the measurement, and the PyroCouple gives good results.
Condition monitoring
e.g. painted bearing housings, driveshafts, rollers and gearboxes
Leaf temperature
e.g. in greenhouses
Tyre manufacturing
Measuring the "green" tyre temperature before tread curing to compensate for seasonal temperature variation
Gas cylinder filling
Monitoring the temperature of each cylinder on a filling rig to improve repeatability in the filled volume and improve filling efficiency

Electrical Installation

2-wire models with 4-20 mA output (option 0)

4-wire models with Type J / K Thermocouple or 0-50 mV output (options 1 to 4)

Note: 4-wire models include a secondary output of the sensor body temperature as a 4-20 mA signal on the power loop. Using this output is optional. On sensors without cooling, the sensor body temperature output provides an indication of the ambient temperature where the sensor is placed, and for cooled sensors it provides confirmation that the cooling is working properly.

Dimensions (mm)

Air Purge Collar

The air purge collar is used to keep dust, fumes, moisture and other contaminants away from the lens. Air flows into the fitting on the side and out of the aperture at the front.

Fixed Mounting Bracket

The L-shaped fixed mounting bracket offers a rigid support for the sensor and allows rotational adjustment about one axis.

Adjustable Mounting Bracket

The adjustable mounting bracket consists of a fixed mounting bracket plus another L-shaped bracket. When assembled as shown, the adjustable mounting bracket offers a rigid support for the sensor and allows two-axis adjustment.

Air/Water Cooled Housing

The air/water cooled housing allows the sensor to withstand ambient temperatures above the normal 70°C limit. Depending on the degree of cooling required, air or water may be used as the cooling fluid. To prevent condensation forming on the lens, an air purge collar is included with this item. The air/water cooled housing must be ordered with the sensor and cannot be fitted by the user.

Laser Sighting Tool

The Laser Sighting Tool screws onto the front of the sensor during installation and shows precisely where the sensor is aiming. Once the sensor has been aimed at the centre of the target and locked in position, the Laser Sighting Tool can be removed. The laser is operated via a latching push button on the front of the tool.

Dual Laser Sighting Bracket

The Dual Laser Sighting Bracket is a sturdy mount for the sensor and provides continuous target sighting while measurements are being taken. Two parallel lasers indicate the centre of the measured spot and are controlled by a remote switch on the electronics module.

View data sheet (PDF)

PID Controllers and Indicators

The PyroCouple may be connected to any of our Pixsys controllers for temperature display, PID control and alarm relay outputs, such as the ATR121 (pictured).

Popular Models

Model Number Optics Temperature Range Output
PC151LT-0 15:1 -20°C to 100°C 4-20 mA
PC151MT-0 15:1 0°C to 250°C 4-20 mA
PC151HT-0 15:1 0°C to 500°C 4-20 mA
PC21LT-0 2:1 -20°C to 100°C 4-20 mA
PC21MT-0 2:1 0°C to 250°C 4-20 mA
PC21MT-4 2:1 0°C to 250°C Type K thermocouple
PC301MT-0 30:1 0°C to 250°C 4-20 mA

More combinations of optics, temperature range and output are available (see Ordering Information).

Extended Cable

The sensor is supplied with a 1-metre cable as standard.

We can provide the sensor factory-fitted with a longer cable (up to 30 metres).

Alternatively you can extend it to any length, depending on the sensor’s output type (4-20 mA is best suited for long distances).


All sensors are calibrated within the published specification at the time of manufacturing. We can provide a 3-point UKAS traceable calibration certificate with new sensors, and we can re-calibrate existing ones. Contact us for details.

Ordering Information