1. Introduction
SDIS is universal configurable sensor for the detection of hot metal and its position. For its
versatility can sensor operate as a hot metal detector (responds to the presence of hot material),
or as a loop scanner (determines the position of the material in the field of view).
Main advantages of SDIS are high speed scanning, comfortable and easy setting and displaying
parameters using the push buttons and display on the unit or remote (RS232, RS485), wide set
of options, two independent sets of detection parameters and switching between them (also
remotely).
2. Principle of operation
SDIS is a scanning sensor. Its field of view is scanned by polygonal mirror. When a hot product
crosses the scanned field of the sensor, the scanned infrared radiation is reflected onto the
photocell of sensor and electronically processed. Depending on the intensity of infrared
radiation is possible to determine whether the requested material is in the field of view, and
according to the current position of the mirror can be derived material position in the field of
view.
The sensor uses highly reliable and proven PbS photocell, designed with regard to the
requirements of the steel industry. The spectral response of a PbS, unlike other types of infrared
radiation detector covers a wide range of hot metal and steel is from 250 ° C.
SDIS scanning system is designed so that the infrared radiation is reflected to the photocell from
each facet of rotating mirror very accurate, even in the case when the entire sensing field is
covered with hot material. Radiation received by photocell is modulated by a rotating mirror. It
provides:
increasing the signal/noise ratio, which allows detection at low temperatures
independent of the interfering background
suppression hysteresis and overload of photocell
increase the life of photocells
Photocell signal processing is performed in modern digital signal processor, enabling fast,
accurate and stable evaluation, wide range of possibility to set of evaluation parameters with
regard to the environment and thus achieve high reliability sensor independently of steam,
scale, material, temperature fluctuations, etc. Parameter setup is simple and intuitive. Thanks to
the built-in display and buttons directly on the device the parameters can be easily monitored
(or change) directly on the sensor. With built-in communication via RS232 and RS485 sensor
can be adjusted and monitored remotely using a PC.
The sensor can operate in two modes:
LS - Loop Sensor - i.e. a sensor for measuring the position of hot material edges in the sensor
field of view. In this mode the sensor must be therefore positioned so as to be in his field of view
located edge of material. On the edge of the hot material occurs pulse on a photocell. Rotation
angle of the mirror motor at the time of detection of the pulse is directly proportional to the
position of the edge of the hot material in the sensor field of view.
