You are here: Home » Products » Infrared-temperature-sensors » Sirius » The-sirius-model-si23

si 23 landing page pic

Utilizing a short wavelength spectral response of 2 to 2.6u, the Sirius SI23 is a perfect choice for induction heating, steel and metal heat treat processes, kilns, vacuum furnaces, research and development applications, welding and composite temperatures above 50°C. Since the emissivity of metallic or shiny surfaces decrease with shorter wavelengths, the SI23 operates at short wavelength, able to provide much better repeatability and accuracy than pyrometers with longer wavelengths.

As standard, the high performance Sirius SI23 is offered with SensorTool Software for recording, analysis, and adjustment of all pyrometer parameters. Accessories include a water-cooling jacket, air purge, scanning mirror, adjustable mounting bracket and swivel base mount.

These units are exceptionally robust due to the fact that the measuring process is performed without mechanically moving parts and because the lens, detector and electronics are housed in a stainless steel cabinet. By utilizing the digital signal process, the Sirius line exceeds standard analog Pyrometers as far as precision and repeatability are concerned.


The infrared energy radiated by the target is centered directly on the detector by factory provided
focused lenses. Lenses are made of BK7, an optical glass which is highly transparent in the spectral region of Sirius SS and SI. If additional windows are necessary, they must offer similar optical characteristics.

The detector is sensitive to infrared radiation in an area called cone of vision. For the spot size diameter Ø of it at shortest, medium and widest distances, if focused, plese. see Chart 2. The cone of vision diameter in front of the lens is about 14 mm. This area has to be kept free from any intervening objects. The spot size diameter for distances not given in the chart can be calculated by interpolation.

Optical Alignment:

The optical alignment of the Pyrometers on the measured object is facilitated by the precise
laser marking which indicates the center of the measured spot. The optical axis is aligned with the mechanical axis of the sensor housing. The laser can be switched on directly at the back of the housing or by an externally installed contact.

Temperature Output Signal:

Sirius Pyrometers offer analog and digital output signals for indication, recording, archiving and controlling of measured process temperatures. The isolated analog output is selectable from 0 to 4 to 20 mA. Zero- and full-scale temperatures are adjustable to cover any portion of the instrument’s available temperature span to a minimum of 51°C. There is a choice of 23 digital communication interfaces: RS 232 or RS 485 max. 57.6 kBd.

Signal Filtering:

For measuring and holding of the highest instantaneous temperature value a peak picker (maximum value storage) is installed to compensate interruptions or attenuations in radiation caused by bursts of steam, smoke or dust. It can be either reset automatically, by an external contact closure or periodically, by user preset clear time. In this last case the highest temperature will be held in a dual storage and will be reset in only one of the two storages, after preset clear time to avoid a decrease of the temperature output, should a short cold period appear just at the reset moment. The exposition time is the length of time it takes for the output signal to reach 90% of a step change in measured temperature. It can be used to filter out rapid variations in temperature and achieve a “more quiet” signal for control or display purposes.

Download Sirius SI23 technical specifications



787 Susquehanna Avenue
Franklin Lakes, NJ 07417
Tel: 201-485-8773
fax: 201-485-8770
Scott Nagle
Rich DeMaddalena


PROCESS SENSORS CORP. (Corporate Headquarters)
113 Cedar St
Milford, MA 01757
Tel: 508-473-9901
Fax: 508-473-2606



© 2017 Process Sensors Corp.