User's Manual

User Manual
3000 SERIES 3
rd
GENERATION ACTIVE RFID
6.8.1 Range alarms
Range alarms are generated based on the absolute measured temperature. The measured
temperature is compared to the range specified by MIN
range
and MAX
range
. If the temperature is not
less than MIN
range
and not greater than MAX
range
the temperature is in range. If the temperature is less
than MIN
range
it is below range and if it is greater than MAX
range
it is above range. A temperature driver
can be configured to generate alarms if the temperature is within range or outside (below or above)
range.
The range also has a hysteresis value Hr. This value is relative to the MIN
range
and MAX
range
thresholds. In the case that the temperature is outside the specified range it must change at least Hr
degrees beyond the MIN
range
or MAX
range
threshold to be considered in range again. Having this
hysteresis can prevent rapid change in alarm status when there is a small fluctuation in temperature
around a threshold value.
The values for the range alarm driver settings are expressed in degrees Celsius (°C).
The following picture depicts the behaviour of the range alarm for a specific temperature curve.
6.8.2 Change alarms
Change alarms are generated by the amount of change in temperature between two sample periods.
A temperature driver will sample its sensor with a configured period. The change in temperature
between two samples is compared to the MIN
change
and MAX
change
thresholds. If the temperature is
decreased more than MIN
change
it is below the change range, if it is increased more than MAX
change
it is
above the change range. Otherwise the temperature change is in range.
Like with the range alarm a temperature driver can be configured to send an alarm if the
temperature change is within range or outside (above or below) range.
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Illustration 21: Temperature range alarms example