METIS M311 / M322 / H311 / H322 (17-pin)
Pyrometer Parameters / Settings
22
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.
6.5.1 Switch-off Verification
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.
6.5.2 Dirty Window Alarm
A signal strength monitoring function detects the degree of contami
nation of the pyrometer‘s optics,
viewing window or identify interferences (dust...) in the IR sensor’s sight path and triggers an alarm if
activated.
6.6
Response Time t
90
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.
6.6.1 Dynamic Adaptation at Low Signal Levels
(only M3)
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.
6.7
Maximum Value Storage (Peak Picker) / Clear Time t
CL
The peak picker always records the highest value during a measurement and holds it until it is deleted
manually or automatically:
Off:
The peak picker is off and the instantaneous value is measured.
Clear externally:
The peak value is cleared manually by an external button or machine contact (con-
Digital Inputs / Outputs
). The external clearing also can be carried
out with the command
lx
Communication via Serial Interface / Interface
Commands
).
Automatically:
The peak value is cleared, if after a "cold break" a new hot measuring object appears
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 correspond
to at least the length of the set response time.
Time 0.01…25 s:
Clears the peak value after the specified time (
Note:
At too long clear times important
temperature information can be lost at sinking temperatures).
Trigger:
The maximum value is manually generated via an external button or machine contact,
as long as the trigger contact is active. The maximum value display appears after re-
leasing the button.