Viewing Alarm Conditions; Events, Fault Thresholds, Faults, And Fault Modes - Symmetricom TSG-3800 Series User Manual

Operating the TSG-3800

Viewing Alarm Conditions

The first line of the response gives the ACTUAL start and stop date and times used
in the calculation. These may vary from the requested times depending on the
actual data available in the module. The lines following give the TDEV in
nanoseconds for the time intervals listed. The time intervals listed range from 0.05
to 1000 seconds, with the highest determined by the observation time period
covered by the command or the available data. TDEV calculations for time intervals
up to one third of the observation period are provided. However, some standards
indicate that an observation period of at least 12 intervals should be used for the
highest accuracy.
Viewing Alarm Conditions
The TSG-3800 reports three types of alarms: Critical, Major and Minor. A Critical
alarm signifies that the output reference is invalid, or the Output modules have no
clock source. A Critical alarm activates the major alarm relays and turns on the
indicator. A Major alarm signifies that the output signals are not synchronized to an
input. A Minor alarm signifies a condition that is not fatal to synchronization, but
could lead to more significant problems. Both Major and Minor alarms contain relay
contacts for Local, Remote, and Audio alarms. When an alarm condition arises, the
CPU module activates corresponding contacts (on the rear panel of the shelf).
An ALARM CUT-OFF switch is available for turning off the Audio alarms. This
switch is on the front panel of the CPU module. The ALARM CLEAR command
(Resetting Alarms, on page 105) turns off the Major, Minor and Audio alarm
contacts.
Alarm messages are available through the EIA-232 port. The EIA-232 port accepts
commands for changing some fault limits. See

Events, Fault Thresholds, Faults, and Fault Modes

An event is an occurrence of a changed condition within the TSG-3800. This
change in condition can be a lost signal (for instance LOS), or instrument related,
for example, module failure. When the magnitude or number of errors surpass a
specific threshold (default or operator settable), a fault condition exists.
A fault mode defines the action that the TSG-3800 takes with the occurrence of a
fault. The operator can assign any of four fault modes to the individual input signal
characteristics of any Input module: Frequency, MTIE, AIS, BPV, CRC, LOS, SSM
and OOF. The operator can also define a threshold for causing a fault. For AIS,
BPV, CRC, LOS, OOF, Frequency, and MTIE, a separate threshold for clearing the
fault can be set.
Table 3-4 shows the relationship between fault modes and TSG-3800 action
followed by a description of each mode.
94 TSG-3800 User's Guide
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Alarm Command, on page 341.
12778474-002-2 Revision F – March 2004