Knowing the exact value of the radiation temperature is essential for the calibration process. It can be measured by either using a contact thermometer (in combination with the determination of the emissivity) or a transfer standard infrared thermometer. This value can then be used to determine the device constant for an initial calibration of the infrared sensors. In order to conduct a post-calibration by customers or local calibration facilities, the calibration temperature should be near the temperatures which occur at the respective applications.
Optris makes use of a transfer standard radiation thermometer CTlaser-PTB (see figure) to measure the radiation temperature of a reference source. The CTlaser- PTB is based on the IR thermometer optris CTlaser. The CTlaser-PTB needs to be traceable to the international temperature scale from 1990 (ITS-90). Thus, it is calibrated by the PTB (German national metrology institute) on a regular basis. ITS-90 is a very good approximation of thermodynamic temperature. It is based on 17 well-reproducible fixed values such as melting points of highly pure metals. Within the framework of ITS-90 the CTlaser-PTB is compared to national temperature standards from the PTB. This comparison within a closed chain of comparative measurements with a known uncertainty in measurement takes place on a regular basis.
Based on the CTlaser-PTB, Optris produces the CTlaser- DCI as a high-precision reference IR thermometer for its customers. The DCI units are produced with pre-selected components supporting high stability of measurement. In combination with a dedicated calibration at several calibration points the CTlaser-DCI achieves a higher accuracy than units from series production.
The optics of an IR thermometer is described by the distance-to-spot-ratio (D:S). Depending on the quality of the optics a certain amount of radiation is also received from sources outside the specified measurement spot. The maximum value here equals the radiation emitted by a hemispheric radiant source. The respective signal change in correlation with a resize of the radiation source is described by the Size-of-source effect (SSE).
As a result of this correlation all manufacturers of IR thermometers use accurately defined geometries for the calibration of their units; meaning depending on the aperture of the radiation source (A) a distance (a) between the IR thermometer and the reference source is defined. Thus, the value specified in datasheets and technical documentation as a measurement field is, in general, a certain defined percentage of this radiation maximum – values of 90 % or 95 % are common.
The newly developed optris Xi 400 combines the benefits of a robust, compact pyrometer and an advanced IR camera. The 80 Hz frame rate allows for the monitoring of fast thermal processes, even including a line-scan function. The spot finder IR camera has an optical resolution of 382 x 288 pixels and comes with an extensive ready-to-use package - including a versatile image processing software.
Due to its compact design and an affordable pricing, the new optris Xi spot finder IR camera is ideally suited for OEM applications.
The new microscope optics for the optris Xi 400 infrared camera allows reliable temperature measurement on tiny objects from 240 µm. In combination with a suitable stand, this enables professional measurement of printed circuit boards and components in the electronics industry. The measuring distance between camera and object is variable between 90 and 110 mm. The built-in motor focus allows for an easy focussing of the camera with the included PIX Connect software. Circuit boards are a core part of electronic devices. They keep getting smaller while having to be more powerful at the same time. Temperatures of assembled circuit boards can easily be measured with the microscope optics of the optris Xi 400 thermal imager, thus identifying overheated areas quickly and preventing possible defects. The causes for excessive temperatures can be manifold: defective components, incorrectly dimensioned circuit paths or poorly soldered joints.
The new compact infrared camera optris Xi 410 combines all the benefits of infrared cameras and infrared thermometers.
The Optris Xi 410 has a fast Ethernet interface and can be powered by PoE. This allows for a simple installation, even if the distance from the PC is large. The built-in hot spot finder function can be used to reliably measure moving objects without having to reposition the camera. If the network connection is interrupted or if the connected PC has a problem, the camera immediately switches to the autonomous stand-alone mode which ensures a continuous measurement and alarm. Thus the reliability of problem detection (typically exceeding a threshold in the context of monitoring a fire outbreak) is maintained. Thanks to this unique feature, the Optris Xi 410 is ideal for all safety applications related to fire prevention, detection of critical hot spots, monitoring of industrial equipment and storage of all kinds.
The Optris Xi 410 incorporates a motorized remote focus, controlled by the free PIX Connect software. The resolution of the camera is 384 x 240 pixels with a frame rate of 25 Hz.
The newly developed optris Xi 80 combines the benefits of infrared cameras and infrared thermometers.
A full 80x80 thermal image eliminates the hunt for the hot spot and tedious positioning required with single spot temperature sensors. The integrated spot finder function will identify the hottest (or coldest) spot in the image and automatically communicate these measurements without an external PC.
A wide range of optics including the new 80° lens equips the Xi 80 to collect and analyze temperature information over a wide target area. The affordable pricing for this unit makes it a realistic alternative to replace existing spot temperature sensors or for OEM applications.