"To De-assert" and Deassertion Hysteresis

After the PXE asserts a state for a sensor, it may de‑assert the same state later on.

To de‑assert a state is to announce the end of the previously asserted, bad state. Below are good state changes that cause the PXE to de‑assert.

Thresholds_deassert

1. above upper critical --> above upper warning

2. above upper warning --> normal

3. below lower warning --> normal

4. below lower critical --> below lower warning

In the threshold settings dialog, the Deassertion Hysteresis field determines a new level to turn on the "de‑assert" action.

This function is similar to a thermostat, which instructs the air conditioner to turn on the cooling system when the temperature exceeds a pre-determined level. "Deassertion Hysteresis" instructs the PXE to de‑assert a state for a sensor only when that sensor's reading hits the "deassertion" level.

Thresholds_deassert

For upper thresholds, this "deassertion" level is a decrease against each threshold. For lower thresholds, this level is an increase to each threshold.

For example:

If Deassertion Hysterresis = 2,

To use each threshold as the "deassertion" level instead of determining a new level, set the Deassertion Hysteresis to 0 (zero).

If you have created an event rule that instructs the PXE to send notifications for deassertion events, setting the "Deassertion Hysteresis" is helpful for eliminating a number of notifications that you may receive in case a sensor's reading fluctuates around a certain threshold.

In This Section

Deassertion Hysteresis Example for Temperature Sensors

See Also

Sensor Threshold Settings

Thresholds and Sensor States

"To Assert" and Assertion Timeout