Switch-Off Level; Switch-Off Verification; Dirty Window Alarm; Response Time T 90 - Sensor Therm METIS M3F1 User Manual

6.6

Switch-off Level

2-color pyrometers measure even with reduced signal strength, such as those occur in a partially filled
measuring field, or dust, smoke, steam, or a window in the beam path between pyrometer and the
measuring object. If the signal strength is too low for a reliable measurement, the measurement is
switched off to avoid measurement errors. In this case, the current output can be set to 0 or 4 mA or
20 mA, and also serial interface settings can be defined.
The switch-off limit can be set between 2 and 90%, recommended for a reliable measurement is a value
of 10%.
INFO: The lower the signal strength, the more likely it can affect the measurement of ambient
light and reflections.

Switch-off Verification

6.6.1
If the signal strength is so low that a switch-off occurs, a time can be entered that defines when this
switching-off actually takes effect.
6.7

Dirty Window Alarm

A signal strength monitoring function detects the degree of contamination of the pyrometer's optics,
viewing window or identify interferences (dust...) in the IR sensor's sight path and triggers an alarm if
activated.
6.8 Response Time t
The response time specifies the time that the pyrometer requires to track 90% of a sudden temperature
change on the signal output.
The response time depends on the requirements of the respective measuring task and can be adjusted.
 If a short response time is selected, the temperature measurement follows the actual temperature
curve accurately. Short setting thus allowing the detection of briefly occurring temperature peaks,
which occur especially in fast heating processes or fast moving samples.
 At longer response times, the measurement signal is smoothed and average values for temperature
fluctuations are formed caused by the inertial measurement.

Dynamic Adaptation at Low Signal Levels

6.8.1
At the beginning of the temperature range at high measurement speeds, the risk of measurement un-
certainty is given by signal noise. This is compensated by the pyrometer by automatically increasing the
response time at the beginning of the temperature range from 1 ms to 4, 8 and finally 16 ms.
6.9

Maximum Value Storage (Peak Picker) / Clear Time t

The maximum value storage always records the highest value during a measurement and holds it until it
is deleted manually or automatically:
Off:
Clear externally: The maximum value is cleared manually by an external button or machine contact
Automatically:
16
Configuring the Pyrometer / Pyrometer Parameters
90
The maximum value storage is off and the instantaneous value is measured.
(connection see 4.1.3 Configurable Inputs / Outputs). The external clearing also
can be carried out with the command lx (see 11, Communication via Serial Inter-
face / Interface Commands).
The maximum value is cleared, if after a "cold break" a new hot measuring object ap-
pears in the measuring beam. "Cold break" means that the measuring temperature
must be below of the beginning of the temperature range. The "cold break" must cor-
respond to at least the length of the set response time.
CL
METIS M3F1