CXR Larus 80-100-400
Issue 1, July 2006
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page
4-6
Cards
4.3110 A watchdog circuit monitors program execution and will restart the
microprocessor if the watchdog timer is not updated.
4.3111 Some failures, such as overflow in the phase correction calculation, may be
caused by the input reference frequency slowly drifting out of tracking range
without causing an excessive offset holdover indication. In normal operation,
the input frequency of the reference will not change in this manner so overflow
would represent a failure of the phase measurement circuits.
4.32
Model 54550 Information Management Card
4.3210 A watchdog circuit monitors program execution and will restart the
microprocessor if the watchdog timer is not updated.
4.3211 The watchdog circuit also checks its serial communications ports. If a failure is
detected, or if any communication channel that has been in operation is lost
(e.g. a link to a track and hold card), the Information Management Card reports
the alarm to the local and remote craft interfaces. If the failure is judged to be
on the Information Management Card, the alarm LED lights and the 54560
Alarm Interface Card is notified.
4.3212 The 54550 Information Management Card monitors alarm leads from all of the
cards and will detect and report a failure on any card.
4.33
Model 54560 Alarm Interface Card
4.3310 The 54560 Alarm Interface Card checks its power supply and will notify the
Information Management Card and signal an alarm if failure is detected.
4.34
Model 54571 through 54577 Output Driver Cards
4.3410 These cards signal an alarm if a failure of any one or more of the twenty
outputs (four in the case of the Model 54577) is detected. The alarm may be
caused by a failure in circuitry on the card. As mentioned, the 54550 and
54560 both report this alarm and the affected card lights its OUTPUT LOSS
LED.
4.35 Failure
Reports
4.3510 Failures reported to the Information Management Card are sent over the local
and remote craft interfaces with the date and time of occurrence and the cause.
In TL1/ITL1, unique failure reports for each of the circuit cards indicate which
card to replace. Refer to CXR Larus Manual 80-800-400, the Model 54550
Information Management Card TL1/ITL1 User Manual, for the format of these
reports.
