Separated Type IR Pyrometers | SIMTRUM Photonics Store

In addition to the integrated infrared pyrometer, we can also provide a separable infrared pyrometer. Different from the structure of the integrated device where the probe and the main unit are integrated into one, the core innovation lies in the physical separation design of the temperature measurement probe (optical sensing unit) and the main unit (signal processing, display control unit). The two achieve data transmission and command interaction through dedicated cables (such as high-temperature resistant shielded wires) or wireless communication modules, and the probe can withstand a maximum temperature of 180℃.

IRTSH Separated IR Pyrometer

Unlike the "direct signal processing within the probe" of integrated devices, the separated main unit can be far away from harsh environments such as high temperatures, dust, and vibration. It precisely amplifies, filters, linearly corrects, and performs data operations on electrical signals, and finally outputs the temperature value through the display screen. It simultaneously supports analog (4-20mA), digital (RS485/Modbus) and other signal outputs, facilitating integration into industrial control systems (such as DCS, PLC) for automated monitoring.

The core advantages of this equipment are mainly reflected in its environmental adaptability and application flexibility: On the one hand, the temperature measurement probe can be designed with high-temperature resistant materials and directly installed in areas near heat sources such as kilns, smelting furnaces, and high-temperature pipelines, while the main unit can be installed in normal temperature and low-interference environments such as control rooms and operation rooms. This not only ensures the temperature measurement accuracy of the probe but also extends the service life of the core components of the main unit. On the other hand, the separation distance between the probe and the main unit can be flexibly adjusted according to the demand, which can cover the "long-distance and high-risk" temperature measurement scenarios that are difficult for integrated equipment to reach, such as temperature measurement in the furnace of large thermal power generation units, surface temperature monitoring of steel continuous casting molds, and high-temperature area inspection of chemical reaction vessels.

Feature

Sparated IR temperature sensor
Withstand high temperatures up to 180°C±1°C/1% measurement accuracy
Multiple temperature measurement ranges are available from-40°C~1200°C
The fastest response time is only 50ms(95%)
The emissivity (0.1 to 1.5) is adjustable
Explosion-proof probe, IP65 protection grade electronic box
Analog quantity and RS485 output simultaneously
Supports the Modbus communication protocol

Parameter	IM-ST-IRP2	IM-ST-IRP8
Supply voltage	12~24V DC
Measurement Accuracy ^*1	Standard: ±1.5℃/1.5%, some models: ±1℃/1%
Repeatability Accuracy ^*2	±0.75℃/0.75%, for some models: ±0.5℃/0.5%
Max. temperature measurement range^*6	-40~100℃	-40~180℃
Temperature resistance of the probe	-40~100℃	-40~180℃
The probe cable is heat-resistant	200℃	260℃（300℃/450℃ Optional）
Min. spot diameter	7mm @ 50mm
Optical resolution	10:1/20:1 is optional, with 90% energy
Temperature coefficient ^*3	0.1K
Spectral range	8~14um
Simulated temperature resolution ^*4	0.1℃/0.1%
Digital temperature resolution ^*5	0.01℃
Response time (95%）	50~5000ms（Adjustable）
Emissivity	0.1~1.5（Adjustable）
Transmittance	0.1~1.5（Adjustable）
Output signal processing	Mean, median, quantile, peak hold, valley hold
Supporting software	SensIRTS
Output method	Simultaneous digital and analog output (customizable for communication output only)
Analog output specification	0-20mA, 0-10V, 0-5V
Analog output load	Current output (max) : 500Ω; Voltage output (min) : 10KΩ (recommended above 30KΩ)
Stabilization time	10min
Digital output mode	RS485/Modbus
Alarm range setting	Digital setting
Alarm output	Digital output
Outgoing line specification	6 lines (default), 4 lines (communication signal only)
Probe wire length	3 m (default), 4/5/8/10 m, customizable
Output cable length	2 m (default), 1/3/5/10 m, customizable
Operating temperature range of the electronic box	-40~85℃
Storage temperature range	-40~85℃
Relative humidity	0-95% no condensation
Earthquake resistance	10~150Hz, 1.5mm double amplitude, 2 hours for each of the XYZ axes
Impact	50G, 10 times in each direction of the XYZ axes
Installation dimensions	Probe M12×1, electronic box: 35mmDIN rail mounting
Shell material	SUS 316
Protection grade	IP65
Explosion-proof mark	Exia ⅡC T6 Ga
Special features	This model allows users to customize the temperature range of the analog output within the specified model specification range. For instance, if a model with a 0-300°C range is selected, the user can define the analog output range as 20-120°C in the SensIRTS software. Then, the 0-20mA output corresponds to 20-120°C, thereby enhancing the resolution of the analog output and facilitating the sensor to play a greater role within the range specified by the user.
Remarks	[1][2] The larger one was measured when the ambient temperature was 23±5℃ and the target object was a standard blackbody at 100℃. Some high-precision models need to be realized with accessories. [3] It was calculated by measuring 100℃ standard blackbody at ambient temperatures of 40℃ and 80℃ respectively. [4] Resolution of analog output. [5] The digital resolution obtained through software or digital communication is the version at the time of release. Any changes will not be notified separately. The latest information on the official website shall prevail.

The relationship between spot size and distance:

Temperature measurement range code
Code	T range	Code	T range	Code	T range	Code	T range
A	-40℃	F	45℃	L	150℃	R	400℃
B	-20℃	G	64℃	M	180℃	S	500℃
C	0℃	H	80℃	N	200℃	T	600℃
D	16℃	J	100℃	P	250℃	U	800℃
E	25℃	K	120℃	Q	300℃	V	1000℃
For example: AR indicates that the temperature measurement range is: -40 to 400℃. BV indicates that the temperature measurement range is: -20 to 1000℃ Note: The temperature measurement range is not an arbitrary combination. The method of taking values is shown in the selection reference table.

Model	Temperature measurement range	Output	Configuration information
IM-ST-IRP2-AJ	-40~100℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-CJ	0~100℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-AN	-40~200℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-CN	0~200℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-AQ	-40~300℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-CQ	0~300℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-AS	-40~500℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-CS	0~500℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-AW	-40~1200℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP2-CW	0~1200℃	RS485&4-20mA	3m probe wire, 2m power cord
IM-ST-IRP8-CJ	0~100℃	RS485&4-20mA	3m probe wire, 2m power cord, probe temperature resistance 180℃
IM-ST-IRP8-CN	0~200℃	RS485&4-20mA	3m probe wire, 2m power cord, probe temperature resistance 180℃
IM-ST-IRP8-CQ	0~300℃	RS485&4-20mA	3m probe wire, 2m power cord, probe temperature resistance 180℃
IM-ST-IRP8-CS	0~500℃	RS485&4-20mA	3m probe wire, 2m power cord, probe temperature resistance 180℃
IM-ST-IRP8-CW	0~1200℃	RS485&4-20mA	3m probe wire, 2m power cord, probe temperature resistance 180℃

Basic composition

The structure of the IR pyrometer is designed around the logic of "capturing radiation - converting signals - processing and calculating - outputting results", and its core components include four major modules:

Optical system: It is equivalent to an "infrared signal collector", composed of components such as lenses, mirrors or optical fibers. Its function is to converge the infrared light radiated by the object under test and focus it on the subsequent infrared detector, reducing the interference of ambient stray light and enhancing the signal strength.
Infrared detector: The core sensing component, responsible for converting the infrared radiation energy gathered by the optical system into measurable electrical signals.
Signal processing circuit: The electrical signals output by infrared detectors are usually weak and noisy. This module enhances, denoising, and digitizes the signals through amplification circuits, filtering circuits, A/D conversion circuits, etc. At the same time, it incorporates algorithms such as environmental temperature correction to eliminate the influence of external factors on the measurement.
Display and Output unit: Responsible for presenting measurement results and achieving signal interaction.

Working principle

The separated IR pyrometer continues the core logic of infrared temperature measurement - relying on Planck's blackbody radiation law, it senses the IR radiation energy emitted by the target object through the IR detector in the temperature measurement probe and converts it into a weak electrical signal. However, unlike the "direct signal processing within the probe" of integrated devices, the separated main unit can be far away from harsh environments such as high temperatures, dust, and vibration. It precisely amplifies, filters, linearly corrects, and performs data operations on electrical signals, and finally outputs the temperature value through the display screen. It simultaneously supports analog (4-20mA), digital (RS485/Modbus) and other signal outputs, facilitating integration into industrial control systems (such as DCS, PLC) for automated monitoring.

The core operation of an infrared pyrometer follows the fundamental law of thermal radiation: any object with a temperature above absolute zero (-273.15℃) will continuously radiate infrared rays (an invisible light) outward, and the intensity and wavelength distribution of the radiation are directly related to the temperature of the object.

According to Planck's law of radiation, the spectral distribution of an object's infrared radiation varies with temperature. The higher the temperature, the shorter the peak wavelength of the radiation and the stronger the total energy of the radiation. According to the Stefan-Boltzmann law, the total infrared radiation power per unit area of an object is directly proportional to the fourth power of the thermodynamic temperature, which is the key basis for the conversion between temperature and radiation energy. The infrared pyrometer captures the infrared radiation of the object being measured through an optical system. The infrared detector converts the radiation signal into an electrical signal, which is then amplified, filtered and compensated by the signal processing circuit. Finally, it is converted into the surface temperature of the object according to the preset algorithm and the reading is output through the display unit. Some models can also synchronously transmit the temperature signal to the control system.

In terms of performance characteristics, the separable infrared pyrometer usually has higher anti-interference ability and customization space: for electromagnetic interference in industrial sites, the main unit can integrate an electromagnetic shielding module; For different temperature measurement ranges (such as -50 ℃ to 1200℃), probes with different spectral responses can be matched. Some high-end models also support probe calibration function. Accuracy calibration can be completed through the main unit without disassembly, reducing maintenance costs.

The emissivity of an object (a parameter characterizing the object's ability to radiate infrared rays, with a value ranging from 0 to 1) directly affects the measurement accuracy. Therefore, most infrared pyrometers have an adjustable emissivity function and can be calibrated according to the characteristics of the material being measured (such as metals and non-metals) to ensure accurate results.

The reference table for the emissivity of common substances is as follows:

Matter	Emissivity	Matter	Emissivity	Matter	Emissivity	Matter	Emissivity
Black fabric	0.98	Water	0.92~0.96	Sand	0.9	Alumina	0.2~0.3
Human skin	0.98	Ice	0.96~0.98	Fur	0.75~0.8	Chromium oxide	0.81
Asphalt	0.9~0.98	Snow	0.83	Carbon powder	0.96	Copper oxide	0.78
Cement	0.96	Glass	0.9~0.95	Black paint	0.97	Iron oxide	0.78~0.82
Concrete	0.94	Ceramic	0.9~0.94	Rubber	0.94	Zinc oxide	0.11~0.28
Soil	0.92~0.96	Gypsum	0.8~0.9	Plastic	0.85~0.95	copper	0.1~0.3
Marble	0.94	Lime	0.89~0.91	Matte paint	0.8~0.95	Stainless steel	0.45
Wood	0.9	Optical fiber	0.9	Lithium electrode sheet	0.8~0.95	Carbon steel	0.69
paper	0.7~0.94	Red brick	0.93~0.95	Graphite	0.7~0.8	Lead	0.6

Note: The emissivity data in the above table is for reference only. The actual emissivity of an object is affected by its surface shape and measurement method. Factors such as frosted surface, polished surface, painted surface, measurement Angle, and target temperature can all influence the actual emissivity.

Therefore, during the use of infrared temperature sensors, the emissivity of objects can be determined through the following methods. For objects with high reflectivity, first measure the surface temperature of the object using a direct-reading thermocouple, then align the infrared temperature sensor with the same area and modify the sensor's emissivity until the temperature is the same as the measured value. At this point, the emissivity can be used as the emissivity of the object. For objects with too low emissivity, it is necessary to use blackbody tape to indirectly measure the surface temperature of the object. Apply blackbody adhesive tape to the surface of a low-emissivity object, and then set the emissivity to 0.95 to measure its temperature.

Note: Even with the above Settings, there may still be errors between the sensor measurement values and the actual object temperature (as the emissivity of some objects changes at different temperatures). Therefore, the high measurement accuracy can be improved by on-site secondary calibration. The digital sensor is equipped with parameter Settings for user secondary calibration. Through these parameters, the secondary calibration of the sensor can be conveniently achieved.

Electrical characteristics

The standard wiring harness of the IRTSH2/8 series IR sensor adopts a six-wire system, while the communication output type uses a four-wire output system. The relevant indicators are as follows:

Indicator	IM-ST-IRP2/8
Core count and specification	6-core AWG26 (default);4-core AWG26 (Customized)
Min. bending radius	25mm (Fixed installation);50mm (Mobile installation)
Lifespan	Bend 4 million times
Temperature range	-20~85℃ (Fixed installation);-5~80℃ (Mobile installation)
Types of connectors	Straight head connector (default);90° elbow connector
Standard length of the wiring harness	2m（default）;1m（customized）
Weight	75g
Definition of wire harness color	Brown: Power positive (+) White: Power ground (-) Blue: RS485-A (+) Black: RS485-B (-) Gray: Analog output Ground (-) Pink: Analog output positive (+)

Definition of Wiring Harness


Definition of four-wire output wiring harness	Definition of six-wire output wiring harness
Note: The power supply has been isolated, the communication has been isolated, and the gray wire AGND has been connected to the sensor housing. Please pay attention when wiring.


Four-wire output wiring diagram	six-wire output wiring diagram

Schematic diagram of a sensor network composed of multiple sensors

Communication protocol

This protocol defines the communication rules and contents between infrared temperature sensors and upper computers as well as PLCS. Based on RS485 communication, the Modbus-RTU protocol has been implemented, which is well compatible with the two mainstream upper-level controllers, PC and PLC. Through this protocol, users can conveniently set multiple parameters of the sensor, read data and store it, which is convenient for later analysis.

Communication parameter Settings: The default communication parameters at the factory are as follows: Baud rate :57600, no parity,8 data bits, and 1 stop bit.
Content of Modbus-RTU protocol: The communication mode of this protocol is question-and-answer mode. The upper computer is the active controller (Master), and the sensor is the passive responder (Slave). In the question-and-answer mode, the active controller sends the corresponding request according to the protocol content, and then the passive responder with a specified ID responds to the request, executes the command, and feeds back the data or execution result.

NOTE:For more details about the agreement, please refer to the relevant content in the user manual section.

Software

Some models of sensors support RS485 communication output function, and parameters can be easily managed and set through the corresponding software.

With this software, the following functions can be achieved: automatically discovering sensors, reading and recording sensor temperature data, setting communication ids, setting the emissivity of the target object to be measured, setting the analog output range, and turning off the analog output.

Installation

1.The sensor probe is uniquely matched with the electronic box

For detachable probe type sensors, each set of sensor probes and electronic boxes have a unique binding relationship. During installation, it is necessary to ensure that the probe ID and the electronic box ID are consistent.

2.The probe connector is non-detachable

For non-detachable probe type sensors, please be careful not to disassemble the probe connector to avoid damaging the precision probe.

Optimal measurement distance

The optimal measurement distance for this IR Pyrometer is 5~2000mm. The distance is a contradiction: a shorter distance can result in a smaller light spot, but the probe is prone to being heated by high-temperature objects, which affects the measurement accuracy. When the distance is relatively far, it will cause the light spot to become larger, making the measurement of small objects inconvenient and also wasting installation space.

In conclusion, ensure that the probe is installed in a constant temperature environment as much as possible, and the measurement spot must be completely inside the object being measured.

Comparison of the measured area and the size of the light spot

To ensure accurate measurement, it is recommended that the size of the object to be measured be 1.5 futian larger than the size of the light spot. The measured temperature is the comprehensive temperature of the measured area. If the measured light spot is larger than the actual object, the measured temperature will include part of the background temperature, causing the measured value to shift towards the background temperature.

Confirmation of installation angles

To ensure accurate measurement, the sensor's axis should be installed as vertically as possible to the object being measured. If space is limited and measurement can only be done at an Angle, it is necessary to ensure that the Angle between the sensor and the normal of the object being measured is less than 45°. Due to different measurement angles, the emissivity of the object being measured varies in a certain direction. Therefore, if the installation Angle changes, the emissivity needs to be reset. If installed at an Angle, please avoid the presence of other high or low temperature heat sources in the direction of light reflection.


Vertical measurement (Recommended)	Tilt measurement (feasible, but with poor accuracy)	Large-angle measurement (not feasible)

Measure large-area high-temperature heat sources

When measuring large-area high-temperature heat sources, due to the scorching effect of the high-temperature heat source on the sensor, the temperature of the sensor will rise or change significantly and continuously, thereby affecting the measurement accuracy. At this time, a orifice plate can be installed in front of the sensor to block the heat source, which can improve the measurement accuracy and stability.

Product Dimensions

We can provide a variety of accessories to assist in measurement. The optional accessories are as follows:

	Isolated USB-RS485 adapter:An RS485 port can be extended on a PC		USB-RS485 adapter with 24V power output:An RS485 port can be extended on a PC, and at the same time, a 24V power output is provided for the sensor to use
	Laser collimator:Can be used for IRTSM series of infrared pyrometer auxiliary alignment of the measurement		Black body adhesive tape:Can be used for temperature measurement or emissivity assessment of low-emissivity objects. The emissivity of the blackbody adhesive tape is 0.95
	Universal mounting frame:Be used for installing IRTSM series high-temperature meters and has the function of universal adjustment		USB direct reading thermocouple:Can be used to contact surface temperature, measuring the emissivity of auxiliary measuring objects.

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