LumaSense Technologies ISR 50-LO - Handbuch (Seite 43)

INFRATHERM pyrometer ISR 50-LO
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9.2 Exposure time (t90)
The exposure time is the time interval when the measured temperature has to be pre-
sent 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 dif-
ference. In the “min” position, the device operates using its time constant of 10 ms.
Longer exposure times can be used for the measurement of objects which have rapidly
fluctuating temperatures to achieve constant temperature reading.
9.3
Maximum value storage (tClear)
If the maximum value storage is switched on always the highest last temperature value
will be displayed and stored. The storage has to be cleared at regular intervals for ex-
changing by a new and actual value.
This feature is particularly useful when fluctuating object temperatures cause the dis-
play 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 following settings are possible:
off: At clear time “off“ the max. value storage is switched off and only momentary values are meas-
ured.
0.01...25 s: If any clear time between 0.01 s and 25 s is set, the maximum value is estimated and held in
double storage mode. After the entered time the storage will be deleted.
extern: The external clearing can be activated and used within an own software (see section 14, Data
format UPP
®
) or via an external contact (for connection see 5.2 Pin assignment of the male
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 current temperature reading at any moment. For this
an external push button or switch has to be connected 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 7 and 5. 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: The maximum value storage follows the function of adjustment of exposure time.
This results in:
• clear time ≤ the adjusted response time is useless
• clear times must be at least 3 times longer than the response time
• only maxima with full maximum value can be recorded, which
appear at least 3 times longer than the response time.
Settings:
min
0.01 s
0.05 s
.
.
.
10.00 s
Settings:
off
0.01 s
.
.
.
25 s
extern/auto/Hold