LumaSense Technologies ISR 12-LO/GS - Handbuch (Seite 18)

IMPAC pyrometers ISR 12-LO/GS
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socket on the back of the pyrometer ). In this case, the storage operates only in single stor-
age , because only a single deletion mechanism is used.
auto: The “auto” mode is used for discontinuous measuring tasks. For example objects are trans-
ported on a conveyer belt and pass the measuring beam of the pyrometer only for a few sec-
onds. Here the maximum value for each object has to be indicated. In this mode the maximum
value is stored until a new hot object appears in the measuring beam. The temperature which
has to be recognized as “hot“ is defined by the low limit of the adjusted sub range. The stored
maximum value will be deleted when the temperature of the new hot object exceeds the low
limit “from“ of the sub range by 1% or at least 2°C. If a lower limit is not entered, the maximum
value storage will be deleted whenever the lower level of the full measuring range has been ex-
ceeded.
hold: The function “hold” enables to freeze the actual displayed pouring stream temperature (or the
current temperature reading if the instrument works not in foundry mode) at any moment. For
this an external push button or switch has to be connected (see 4.1.1 Connector pin J) which
holds the temperature reading as long as the contacts are closed.
Operation note:
dependent on the settings the maximum value storage either works in single storage mode
or in double storage mode:
Single storage: the single storage is used when you want to reset the stored value using an external im-
pulse via one contact closure from an external relay (i.e. between two measured objects). The relay contact
is connected directly to the pyrometer between pins J and K. This mode allows a new value to be estab-
lished, after each impulse from the reset signal.
double storage: when entering the reset intervals via push buttons or PC interface the double storage is
automatically selected. This mode utilizes two memories in which the highest measured value is held and is
deleted alternately in the time interval set (clear time). The other memory retains the maximum value
throughout the next time interval. The disadvantages of fluctuations in the display with the clock frequency
are thereby eliminated.
Note: In pouring stream mode the exposition time follows the function of adjustment of maxi-
mum value storage. This can be used in case of interruptions in the pouring stream:
• The setting of a clear time for the maximum value storage stores always the highest
value during the measurement value calculation
• Setting a value for the exposure time is smoothing this stored values so that even with
interruptions in the pouring stream a reasonable temperature calculation can be done.
8.5 Operating mode (1 / 2 / M)
The series 12 pyrometers are designed for use in ratio mode. Additionally the pyrome-
ters can be used in two other modes:
In the mono mode the pyrometer only measures in one wavelength and the ratio mode
is off. In this case the operating mode is equivalent to a conventional 1-color pyrome-
ter (see 8.2 Emissivity).
The metal mode is a special mode which calculates the temperature combining the ratio and the 1-color
signal with an algorithm. The metal mode can be used to determine the temperature of metals and alloys
with unknown emissivity ratio (K). It should be used only for a short time to achieve a good approximation of
the object temperature if the temperature reading in 2-color or 1-color mode seems to be incorrect. After this
the pyrometer has to be switched back into 2-color mode and the temperature reading has to be corrected
with the adjustment of the emissivity slope K until the instrument shows the temperature determined in the
metal mode. A condition for the use of the metal mode are settings of
ε
= 1 and K = 1.
(Note: also the metal mode can be affected by the setting of the switch-off limit, see 8.6)
8.6
Switch-off limit (OFF / %)
The switch-off limit is a function to avoid measuring errors caused by too low signals.
Ratio pyrometers are able to measure temperatures correctly even with very low sig-
nals, i.e. for example through a dirty viewing window or if dust exists in the field of
view or if the spot is not filled by the measuring object. If the signal is too low for a
correct measurement, the pyrometer interrupts the measurement and displays 1° below of beginning of the
temperature range. Depending of the application the switch-off limit can be adjusted between 2 and 50%, ex
works at delivery set to 10%.
Settings:
mono mode
ratio mode
metal mode
Settings:
2%
. . .
50%