15
Note
: When the system is not energized, the ready status
will be OFF due to absence of the MV sensor signal allowing
switching synchronization. When the system is energized with
at least 1.5 kV rms (at the suggested voltage divider) and the
frequency range is within the n/- 1.4 Hz value, varia-
tion within this range is fully accepted and compensated by the
control system setting to the ready condition (Ready ON).
−
Watchdog Green (solid-state output) OR Lamp ON
: the
system shows that it is fully alive. The watchdog is internal
hardware circuitry that constantly checks the integrity of the
system and ensures that the software is running properly.
The watchdog signal will be OFF when a faulty switch status
that could be caused by a hardware problem is present.
−
Alarm ON
. The dry contact of the alarm status is closed.
Installation of a lamp (conforming to the current capability
of the contact) is recommended. Alarm ON indicates a fault
concerning power part positioning OR a response to internal
diagnostics, as described below:
• Incorrect positioning at startup (which can be adjusted by
means of the commissioning procedure described below
(only feasible in a de-energized condition)
• Bad behaviour during actuations (can be adjusted by
means of the commissioning procedure but only feasible
in a de-energized condition and only by qualified ABB
personnel)
• Bad response to the Micro Motion self-check (can be ad-
justed by means of the commissioning procedure but only
feasible in a de-energized condition and only by qualified
ABB personnel)
Note
: the Micro Motion Test is self-executed by the system
when 24 hours have elapsed without operation with the sys-
tem in the closed position. This diagnostic check produces a
negligible movement of the power part but is sufficient to allow
the system to check the actuators, power part response and
feedback coherence of the redundant position sensing built in
the system.
Provided
by
Northeast
Power
Systems,
Inc.
(NEPSI)
