LumaSense Technologies IS 12-Al/S - Manual (Page 23)

IS 12 AI & IS 12-AI/S Parameters 23
5 Parameters
5.1 Emi (emissivity )
For a correct measurement, it is necessary to adjust the emissivity. This emissivity is the
relationship between the emission of a real object and the emission of a black body radiation
source at the same temperature (this is an object which absorbs all incoming rays and has an
emissivity of 100%). Different materials have different emissivities ranging between 0% and
100% (settings at the pyrometer between 10 and 100%). Materials with shiny surfaces have a
lower emissivity than materials with rough surfaces. The emissivity setting of the pyrometer
needs to be adjusted accordingly. Emissivity values of aluminum are listed below:
Aluminum temperature of polished surfaces of smooth surfaces
360 to 500 °C 14% 30 to 36%
> 500 °C 14% 33 to 43%
5.2 Exposure Time (t
90
)
The exposure time is the time interval when the measured temperature has
to be present after an abrupt change so that the output value of the
pyrometer reaches a given measurement value. The time taken is to reach
90 % of the recorded temperature difference. In the “0.00” position, the
device operates using its time constant.
The dynamic exposition time adjustment prolongs the exposure time at the lower range limit.
5.3 Clear time of the maximum / minimum value storage
(t
CL
)
If the maximum value storage is always switched on, the highest last
temperature value will be displayed and stored. The minimum value storage
saves the lowest measurement taken during a reading. The storage has to be
cleared at regular intervals and be replaced with a new and actual value.
This feature is particularly useful when fluctuating object temperatures cause
the display or the analog outputs to change too rapidly, or the pyrometer is
not constantly viewing an object to be measured. In addition, it may also be beneficial to
periodically delete and reset the stored maximum values.
The maximum value storage value has two different operating modes:
Single Storage: The single storage is used when you want to reset the stored value using
an external impulse 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 established, after each impulse from the reset
signal.
Double Storage: When entering the reset intervals via push buttons or PC interface the
double storage mode is automatically selected. This mode utilizes two memories in which
the highest measured value is held and is deleted alter-nately in the time interval set (clear
time). The other memory retains the maximum value throughout the next time interval.
Settings:
off
0.01 s
0.05 s
...
10.00 s
Settings:
off
0.01 s
...
25 s
extern
auto