PyroEpsilon Fixed Infrared Temperature Sensor with Adjustable Emissivity




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  • Temperature ranges from -20°C to 500°C
  • 2-wire 4-20 mA output for measured temperature
  • Emissivity adjustment via separate 4-20 mA input
  • 4-20 mA input signal may be supplied by the PPT245 indicating controller (pictured), the PyroTune emissivity adjuster, or any other source such as a PLC output
  • Stainless steel housing, sealed to IP65
  • Choice of optics to suit all target sizes
Field of View -20°C to 100°C 0°C to 250°C 0°C to 500°C
2:1 PE21LT PE21MT
15:1 PE151LT PE151MT PE151HT
30:1 PE301LT PE301MT PE301HT

For sensors with 2:1 optics and 0°C to 500°C temperature range, contact Calex.


General Specifications

Output: 4-20 mA (two-wire, on power loop)
Accuracy: ± 1% of reading or ± 1°C whichever is greater
Repeatability: ± 0.5% of reading or ± 0.5°C whichever is greater
Emissivity Setting: Adjustable from 0.2 to 1.0 via 4-20 mA input
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)
Input Impedance: 50 Ω

The sensor is supplied with a cable length of 1 m as standard. Longer lengths are available to order; please contact Calex for more information.

Connecting the PyroEpsilon:

1. Connect only the power wires PWR+ and PWR- to a 24 V DC powered 4-20 mA measurement loop. Connect the emissivity input wires IP+ and IP- to each other, and do not connect them to the power supply.

2. Obtain a temperature reading without emissivity adjustment.

3. Connect IP+ and IP- to a 4-20 mA current source if emissivity adjustment is required.

Electrical Installation

Dimensions (mm)

PPT245 Indicating Controller

The PPT245 indicating controller provides a 4-20 mA signal for adjustment of the PyroEpsilon’s emissivity setting, as well as a display of the measured temperature and configurable relay outputs for alarm or control.



PyroTune Emissivity Adjuster

Provides a 4-20 mA signal for emissivity adjustment. The push-buttons allow adjustment of the emissivity setting, and the built-in display shows either the emissivity setting or the milliamp signal being supplied to the sensor.


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 fine 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 fine 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. 

Protective Plastic Window

When fitted over the lens of the sensor, the protective plastic window in stainless steel holder provides mechanical protection and helps retain fragments of lens in case of damage. Adjust the sensor’s emissivity setting to compensate for the presence of the window for maximum accuracy. This accessory is ideal for the food and pharmaceutical industries.

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