Hazardous Area Classification
Ambient Temperature Rating: -20°C ≤ Ta ≤ 70°C
ATEX Classification: Ex II 2 G
IECEx Classification (Gas): Ex ia [ia Ga] IIC T4 Gb
Sensing Head (ambient temperatures below 115°C)
Ambient Temperature Rating: -20°C ≤ Ta ≤ 115°C
ATEX Classification: Ex II 1 G
IECEx Classification (Gas): Ex ia IIC T4 Ga
Sensing Head (ambient temperatures below 180°C)
Ambient Temperature Rating: -20°C ≤ Ta ≤ 180°C
ATEX Classification: Ex II 1 G
IECEx Classification (Gas): Ex ia IIC T3 Ga
Maximum DC Input Voltage
Ui = 28 V
Maximum Input Current
Ii = 93 mA
Maximum Input Power
Pi = 0.651 W
Maximum Internal Capacitance
Ci = 5.17 nF
Maximum Internal Inductance
Li = 1.99 µH
ATEX Certificate Number
IECEx Certificate Number
IECEx CML 22.0001X
JapanEx Certificate Number
UKCA Certificate Number
The ExTempMini is an intrinsically safe pyrometer. It measures the temperature of surfaces in hazardous areas without contact, and provides a direct 4-20 mA output. It is certified to ATEX, IECEx, UKCA and JapanEx standards.
Explosion proof pyrometers typically have bulky, expensive housings, however because the ExTempMini uses Intrinsic Safety as the method of protection, it is compact and low-cost.
Measurement Temperature Range
-20°C to 1000°C (see table of Model Numbers)
Two-wire 4 to 20 mA (loop powered)
Maximum Temperature Span
Minimum Temperature Span
± 1°C or 1%, whichever is greater
± 0.5°C or 0.5%, whichever is greater
Emissivity Setting Range
0.20 to 1.00 (pre-set to 0.95)
Emissivity Setting Method
User configurable via optional USB / RS-485 adapters
Response Time, t90
240 ms (90% response)
12 to 24 V DC ± 5%
Minimum Sensor Voltage
11.4 V DC
Maximum Current Draw
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 ExTempMini detects only the wavelengths of infrared radiation that are not absorbed by the atmosphere.
Main Enclosure: Painted Aluminium
Sensing Head: Stainless Steel 316
Main Enclosure: 99 x 65 x 35 mm
Sensing Head: Ø 20 x length 69 mm including cable gland (see Dimensions)
Main Enclosure: 2 x mounting holes, use M4 socket head screws
Sensing Head: M20 x 1.5 mm thread, length 20 mm, supplied with two mounting nuts
Cable Length (Sensing Head)
Choice of 5 m, 10 m or 25 m factory-fitted. Contact Calex for information about extending cable.
Weight with Cable
475 g (5 m cable), 625 g (10 m cable), 1075 g (25 m cable)
Removable screw terminal blocks (see Connections). Conductor size 22 AWG to 14 AWG (0.326 mm2 to 2.08 mm2)
Output Cable Gland
Suitable for cable diameters 3.5 to 7.0 mm
Main Enclosure and Sensing Head: IP65 (NEMA 4)
Ambient (Operating) Temperature Range
Main Enclosure: 0°C to 70°C
Sensing Head: 0°C to 180°C
Ambient Pressure Range
Main Enclosure and Sensing Head: 80 kPa (0.8 bar) to 110 kPa (1.1 bar)
Main Enclosure and Sensing Head: Max. 95% non-condensing
Electromagnetic Compatibility Standards
Conforms to EN 61326-1, EN 61326-2-3 (Industrial).
The ExTempMini’s ATEX, IECEx, UKCA and JapanEx certification makes it suitable for many applications in hazardous areas involving gas.
Petrochemical - condition monitoring
Bearing, gearbox and motor housing surface temperatures in refineries and chemical plants can be monitored without contact, eliminating the need to replace contact probes that are easily damaged by vibration.
Petrochemical - liquid storage and processing
The sensing head can be positioned in a Zone 0 environment such as the top of a tank of hazardous liquid or chemical reactor, to measure the surface temperature of the liquid, in conjunction with suitable air purging or protective viewport.
Gas cylinder filling
The surface temperature of cylinders of flammable gases is monitored with the ExTempMini as they are filled. The Group IIC, T4 (or T3 depending on ambient temperature) classification of the sensing head makes it suitable for almost all gases including propane, butane, hydrogen and acetylene. The temperature of each cylinder is measured on the filling rig to help detect fault conditions in filling, to calculate the final filled volume (in conjunction with the pressure), to ensure the volume is repeatable, and to improve the filling rate.
Solvents in automotive painting can lead to the presence of a hazardous gas Zone. The intrinsically safe ExTempMini may be used to measure the temperature of containers and vessels, the surface temperature of liquids, and the temperature of painted surfaces.
The stainless steel 316 housing of the ExTempMini's sensing head, and its intrinsically safe certification, make it well-suited for use on offshore platforms.
More information about the electrical installation of the ExTempMini, including pin numbering for the MTL 5541 isolator, is available in the data sheet and manual. See “Downloads” for more information.
Connections: ExTempMini (also showing optional USB adapter model LCT) (below)
Network layout: ExTempMini with optional RS-485 interface, model LCT-485 (below)