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5
Time Function Processing
5.1 Peak Picker
The Peak Picker function can be used to monitor the highest temperature
measured by the thermometer. This feature is useful especially for moving
targets and/or where the target is obscured partially e.g. a steel slab on a
rolling mill where parts of the surface are covered with scale. The 'clean' area
will be at the higher (i.e. true) temperature. The Peak Picker used in Profibus
processors has the following features. Refer to Fig. 9.
Threshold level:
ON delay:
OFF delay:
Mode:
Decay rate:
Time
Fig. 9 Graphical representation of the Peak Picker time function
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Temperature above which the Peak Picker is active, used
in conjunction with the 'ON' and 'OFF' delay.
Time period between the temperature rising above the
threshold level and the Peak Picker function switching on
Time period between the temperature falling below the
threshold level and the Peak Picker function switching off.
In 'Hold' mode, at the end of the 'OFF' delay, the
temperature output value is held constant until the
temperature input next rises above the threshold level.
In 'Reset' mode, at the end of the 'OFF' delay, the
temperature output signal falls to 'under-range' until the
temperature input next rises above the threshold level.
The Peak Picker can be 'Reset' at any time by using the
CMD input. See 3.3.2
A user-adjustable value at which the stored temperature
output signal decays.
'ON' Delay
Adjustable decay rate
Threshold level
User Guide
'Hold'
mode
'OFF' Delay
'Reset'
mode
S4970092
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