PyroUSB (Discontinued – see PyroUSB [New Version])
Infrared temperature sensor with 4-20 mA output and USB
Alternative Product:PyroUSB

Sensor Features

  • Temperature range: -40°C to 1000°C
  • Rescalable 4 to 20 mA two-wire output
  • Fully configurable
  • USB interface (cable and Windows software included)
  • Use the USB output only, the 4-20 mA output only, or both together

Software Features

  • Display of measured temperature
  • Sensor configuration
  • Scrolling temperature chart
  • On-screen and audible alarms
  • Data logging to Excel-compatible file

Key Feature Tags

Read more

General Specifications

Temperature Range
-40°C to 1000°C
Optics (see Field of View Diagrams)
15:1 (model PU151)
30:1 (model PU301)
Diameter 5mm @ distance 100mm (model PUCF)
4 to 20 mA (linear with temperature) and USB
Via USB port conforming to USB 2.0, using included cable and PC software
±1% of reading or ±1°C whichever is greater
±0.5% of reading or ±0.5°C whichever is greater
Emissivity Setting
0.1 to 1.0
Response Time, t90
240 ms (90% response)
Spectral Range
8 to 14 μm
Supply Voltage
24 V DC (28 V DC max)
Sensor Voltage
6 V DC min
Max Loop Impedance
900 Ω
Maximum Span (4-20 mA output)
Minimum Span (4-20 mA output)

Software Specifications: CalexSoft

Operating System
Windows XP or newer
Temperature display, scrolling temperature chart, sensor configuration, data acquisition with scheduled start, on-screen and audible alarms, OPC Server interface
Data log file format
.csd (comma separated text format, may be imported to spreadsheet software such as Excel)
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 Calex sensors detect only the wavelengths of infrared radiation that are not absorbed by the atmosphere.

Mechanical Specifications

Stainless Steel
25 mm diameter x 106.5 mm long
Thread Mounting
M20 x 1 mm pitch
Weight with Output Cable
175 g
Output Cable Length
1 m as standard (cable lengths up to 30 m available on request)
USB Cable Length
1 m

Environmental Specifications

Environmental Rating IP65
Ambient Temperature Range 0°C to 70°C
Relative Humidity 95% max. non-condensing

Electromagnetic Compatibility Standards

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


The analogue and USB outputs of the PyroUSB make it ideal for use in the factory or on the test bench.

There are many more applications in which the PyroUSB may be used with great success. For more information on using this sensor in your application, or for help in choosing the most suitable model, please contact Calex.

Typical Applications

The PyroUSB can measure temperatures as low as -40°C, so it is especially suitable for non-contact temperature measurement of frozen food.

For individual food items or moulds on a moving conveyor, the peak/valley-hold processing capability of the PyroUSB may be used to ensure only the temperature of the food item or the mould itself is measured.

An internationally-famous manufacturer uses the PyroUSB to measure chocolate bar mould temperatures prior to automatic deposition of molten chocolates.
R&D and Laboratory
The USB interface makes the PyroUSB ideal for use on the test bench in lab and R&D applications.

The included software can log data in a simple, Excel-compatible comma-separated text format, and is also compatible with LabView and other software via the built-in OPC Server
Brake testing
Non-contact measurement of brake disc temperatures between -40°C and 1000°C, for discs made of non-metals such as carbon.
The all-in-one design of the fully-configurable PyroUSB provides a linear analogue temperature output directly from the sensor body. It is ideal for measurement of temperatures on thermoforming machines without the need for signal converters or separate electronics boxes.
Bearing testing, gearbox testing
Measurement of external housing surface temperature on bearing and gearbox test rigs, with data acquisition directly to a PC via USB.
Furnaces and ovens
The PyroUSB may be positioned outside a furnace or oven, and aimed in through a window or purged sight tube. The reflected energy compensation feature reduces errors from reflections, and helps ensure an accurate reading of the temperature of the object inside the furnace.

The PyroUSB has a 4-20 mA output and USB communications. It is possible to use the outputs individually, or both at the same time.

Electrical Installation

Current Output Only

Current Output and USB Connected Simultaneously

USB Only

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 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.


PID Controllers and Indicators

The 4-20 mA output of the PyroUSB may be connected to any of our indicating controllers, which provide temperature display, PID control and alarm relay outputs. Our panel-mount PID controllers, such as the ATR121 (pictured) are priced from just £72.

This product range has been upgraded. See PyroUSB (New Version)