71
INM MTL SUM5 Rev 7
DRAFT - 09 June 2021 DRAFT - 09 June 2021
30 ADDITIONAL FEATURES
30.1 Automatic Reset
Once a channel has been acknowledged and its input has returned to normal the
alarm can be set to automatically reset without the operator having to press the reset
pushbutton.
30.2 Non Latch Sequence – (No Lock In)
Alarms can be set to non lock-in, which allows the alarm to automatically return to the
non alarm state as soon as the signal input returns to normal.
30.3 Ringback Sequence
Ringback sequence is used to inform the operator both visually and audibly that an
alarm condition has cleared and the channel can be reset to its normal off state. When
a contact returns to normal the associated window will ash at approx ½ the speed of
a normal alarm and the audible will sound. This identies the specic alarm and informs
the operator that the alarm can be reset to its normal off state.
30.4 First Up Sequences
When monitoring devices with interlinked functions such as a turbine or compressor it is
often important to know the specic alarm that occurred rst, as it will invariably result
in cascade of secondary alarms. This allows the operator to focus on the root cause of
failure and therefore limits the downtime and associated costs. This is achieved by having
the rst-up alarm ashing in a different manner compared to the subsequent alarms.
Four different rst-up sequences are available F0, F1, F2 and F3 as detailed below and in
the following sequence tables.
F0 The standard mode adopted by Eaton Electric, which indicates the rst-up
alarm by ashing at twice the rate of subsequent alarms.
F1 In this mode subsequent alarms appear in the acknowledged state, hence they
do not ash. The audible device does not operate when subsequent alarms
occur, unless still operating from the rst alarm. The acknowledge pushbutton
will reset the rst-up indication.
F2 In this mode all subsequent alarms do not ash, they will however operate the
audible device. The acknowledge pushbutton will reset the rst-up indication.
F3 In this mode initial alarms appear with an intermittent ash rate and
subsequent alarms ash at a steady rate. On acknowledge subsequent alarms
revert to the steady on state and only the rst alarm continues to ash at a
slower rate.
Please note auto reset and non lock- in functions are not recommended when using rst
up sequences as the true sequence of events cannot be guaranteed.
The most common sequences are detailed below:-
To Next Page
Loading...
Need help?
General
