Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 228 of 265
Condition CPU Fault Action
Green Correspondence Failure
Compares “required” states against actual
states or the dual voltage monitors disagree.
Measured by voltage on drive. Functions with
no external load. Monitoring cannot be
disabled.
See section 33.3 for details of the options a)
to d) available for Fault Actions.
Main
CPU
a) Controller Shutdown
b) Stream direct to part-time state
Sig
Mon
a) Controller Shutdown
b) Controller Shutdown
Green / Green Conflict
If caused by an extra green being forced ON
in error, then this fault is confirmed as a
Green Correspondence failure; see above.
If caused by a software, configuration or run-
time fault in main processor in which it
requests that two conflicting aspects are
illuminated, then:
1) The main processor firmware includes a
check to detect the fault before the request is
actually transmitted and results in Controller
Shutdown before the aspects are actually
illuminated.
2) If the fault is not detected by the main
processor firmware, then the Signal Monitor
will confirm the conflict fault in the actual
states of the signals. Measured by voltage on
drive - functions with no external load.
Monitoring cannot be disabled.
Main
CPU
Controller Shutdown
Sig
Mon
Controller Shutdown
Green / Amber Conflict or
Green / Red+Amber Conflicts
Which ambers to consider is configurable,
and the whole check can be disabled if
required.
If caused by an extra green or amber being
forced ON in error, then this fault is confirmed
as a Green or Amber Correspondence failure;
see earlier in the table.
If caused by a software, configuration or run-
time fault in main processor in which it
requests that two conflicting aspects are
illuminated, then the fault is confirmed as for
Green / Green Conflicts above.
Main
CPU
Controller Shutdown
Sig
Mon
Controller Shutdown