User`s guide

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USER’S GUIDE
Network Management Card
51
Thresholds. For each sensor, you set the same types of thresholds for temperature
and (if supported) humidity measured at the sensor.
Hysteresis. This value specifies how far past a threshold the temperature or humidity
must return to clear a threshold violation.
• For Maximum and High threshold violations, the clearing point is the threshold minus
the hysteresis.
• For Minimum and Low threshold violations, the clearing point is the threshold plus the
hysteresis.
Increase the value for Temperature Hysteresis or Humidity Hysteresis to avoid multiple
alarms if temperature or humidity that has caused a violation then wavers slightly up
and down. If the hysteresis value is too low, such wavering can cause and clear a
threshold violation repeatedly.
Example of falling but wavering temperature: The minimum temperature threshold
is 33°F, and the temperature hysteresis is 3°F. The temperature drops below 33°F,
violating the threshold. It then wavers up to 34°F and then down to 31°F repeatedly, but
no clearing event and no new violation occur. For the existing violation to clear, the
temperature would have to rise above 36°F (3°F past the threshold).
Threshold Description
Maximum If the threshold for maximum temperature or for maximum humidity for the sensor
is exceeded, an alarm occurs.
High If the threshold for high temperature or for high humidity for the sensor is
exceeded, an alarm occurs.
Low If the temperature or humidity drops below its low threshold for the sensor, an
alarm occurs.
Minimum If the temperature or humidity drops below its minimum threshold for the sensor,
an alarm occurs.