Chapter 5: Using the Web Interface
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Example: When Hysteresis is Useful
This example demonstrates when a deassertion hysteresis is useful.
The current critical threshold for Outlet 1 is set to 10 amps (A). The current
draw rises to 11A, triggering a Current Critical alert. The current then
continues to fluctuate between 9.8A and 11A.
With the hysteresis set to 0.9A, the Dominion PX continues to indicate that
the current in Outlet 1 is above critical. With the hysteresis disabled (that
is, set to zero), the Dominion PX would de-assert the condition each time
the current dropped to 9.9A, and re-assert the condition each time the
current reached 10A or higher. With the fluctuating current, this could
result in a number of repeating SNMP traps, and/or an e-mail account full
of repeating SMTP alert notifications.
Example: When to Disable Hysteresis
This is an example of when you want to disable the use of hysteresis for
outlets.
The upper non-critical threshold for current in Outlet 2 is set to 8A. In
normal usage, Outlet 2 draws 7.6A of current. A spike in demand causes
the current to reach 9A, triggering an alert. The current then settles to the
normal draw of 7.6A.
With the hysteresis disabled (that is, set to zero), the Dominion PX
de-asserts the condition once the current drops to 7.9A. If the hysteresis
remained enabled and the current never dropped to 7.0A, the outlet would
still be considered above non-critical. The condition would not de-assert,
even if the current draw returned to normal.
Setting Up Event Logging
By default, the Dominion PX captures certain system events and saves
them in a local (internal) event log. You can expand the scope of the
logging to also capture events in the NFS, SMTP, and SNMP logs.
Note: When configuring the Dominion PX to use more than one logging
method, configure each method individually and apply the changes before
configuring the next.