LumaSense Technologies ISR 12-LO/GS - Handbuch (Seite 13)

IMPAC pyrometers ISR 12-LO/GS
13
Spot
6.2 Spot size table
Optical head with line spot width Optical head with line spot width
= 5% of measuring distance = 12% of measuring distance
measuring distance
a [mm]
spot [mm]
width x height
measuring distance
a [mm]
spot [mm]
width x height
340 17 x 1.6 340 41 x 1.6
500 25 x 2.4 500 60 x 2.4
750 37.5 x 3.8 750 90 x 3.8
1000 50 x 5 1000 120 x 5
2000 100 x 11 2000 240 x 11
4500 225 x 24 4500 540 x 24
Note: The table mentions spot sizes for different fixed measuring distances of the opti-
cal head. Deviations from the adjusted measuring distances create a certain blur
which results in an enlarged spot size.
6.3
Aligning the optical head to the pouring stream
The optical head has to be aligned in that way that the spot is partially filled by the pouring stream. If the
pouring stream is moving, the stream should not leave the spot.
For a correct measurement of a pouring stream it is necessary that the measuring
signal has a certain minimum level of 10 to 20% (i.e. the size of the pouring stream and
the spot size must have a certain relation). The signal level is displayed in the software
InfraWin in the window “color bar” (see “relative signal” in 9.8), be sure the emissivity slope is
adjusted correctly (see 8.2). If the signal is too low at the required measuring distance, the spot
also can be adjusted diagonal to the pouring stream to increase the signal strength, but regard not
to touch the “beard” at the top or the form edge.
6.4
Aligning the optical head with help of the laser targeting light
For correct alignment of the optical head the built-in laser targeting light has to be used. The laser creates a
line spot in the dimensions of the measuring spot. The size of this line varies for the different measuring dis-
tances. As the alignment of the optical head is quite difficult during the pouring process it is recommended to
do it before the process starts. This can be done with a white sheet of paper which is hold at the position of
the pouring stream. The laser line can be easily recognized on the paper for an accurate alignment.
If the laser targeting light is switched on, the display is blinking with the value “8000”, the analog output
keeps the last measurement value.
The laser targeting light can be switched on and off either by pressing the button at the housing or by using
an external contact (see 4.1 Pin assignment for the connector on the bottom side of the pyrometer) or
via PC and the software InfraWin. After two minutes the laser targeting light is switched off automatically.
Warning: To reduce the risk of injury to the eyes, do not look directly into the
targeting laser and do not point the targeting laser into anyone's eyes.
The instrument is equipped with a class II laser that emits radiation.
Note: To prevent the damage of the laser, the pilot light switches off automatically if the
internal temperature of the device exceeds approx. 55°C (it can switched-on again,
if the internal temperature is lower than 55°C)!