C300 operating behaviors
Time management in the C300 Controller
R301.1 Experion C300 Controller User's Guide 183
11/06 Honeywell
C300 operating behaviors
This section describes some of the C300 Controller’s features and operating behaviors
related to event and alarm reporting.
Time management in the C300 Controller
The C300 Controller and the Series C FIM4 require a reliable and high quality time
source to correlate events from other devices in the system. Network Time Protocol
(NTP) or Simple Network Time Protocol (SNTP), from a dedicated time server is the
preferred time source for the controller, although the controller can operate using one of a
number of time sources. Other time sources can include CDA time and the internal Wall
Clock Time (WCT) of the controller.
See Setting up time synchronization in the Supplementary Installation Tasks Guide for
information on setting up a system time server. The time source for the controller is
defined in the C300 block during configuration.
The controller connects to the time source during its startup routine and receives
subsequent updates at regular intervals.
Adjustments to time occur in the controller tomaintain synchronization with the time
source. If the differnence between the system time source and the controller’s wall clock
time (WCT) is less than 5 minutes, then time is adjusted in increments. If the controller’s
WCT differs by more than 5 minutes with the time source, controller time is set to match
the time source with an immediate correction. An information notification is generated
by the controller and sent to the events server.
Time synchronization between a primary and secondary C300 Controller is maintained
by the redundancy sub-system. The primary controller passes its WCT to the secondary
controller. Time adjustments are made to achieve time synchronization between the
redundant controller pair.
The C300 also maintains a Sequence Of Events (SOE) clock to synchronize to the system
time source (whenever one is available). Time adjustment occurs in a similar manner,
except that the SOE clock will be set to match the time source whenever a difference
between the source and the SOE clock exceeds 15 seconds.
Note that in the absence of an NTP time source, SOE event correlation is degraded across
a controller switchover. Events occurring before switchover are consistent, and events
occurring after switchover are consistent, but the timestamps of the two groups of
timestamps (before and after switchover) are degraded with respect to each other.
During normal operation the C300 Controller maintains a timeout on the current system
time source so that the controller can detect an interruption and switch to an alternative
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