15
Interlockings It has been mentioned in the section describing
the functions of an alarm channel that each
channel is provided with three interlocking in-
put types, 1, 2 and 3, and one interlocking
output type, 0.
The interlocking input type 1 prohibits, when
energized, only the channel reflash signal type A
from being transmitted, while the interlocking
input type 2 blocks the whole alarm channel and
if the blocking drops of while the channel is still
active, the channel will be indicated as an ac-
knowledged alarm. The interlocking input type
3 also blocks the whole channel but returns as a
new alarm when the interlocking drops of. The
interlocking output type 0 is activated by an
alarm channel being activated or by one of the
interlocking inputs being activated. The feature
mentioned last enables the annunciator unit to
be programmed with up to eight interlocking
levels.
Note!
If more than three interlocking levels are used it
will effect the resolution on the time stamp for
the event register.
The interlockings are distributed between the
different channels via eight internal interlock-
ing lines, see figure on page 16.
Each channel can be connected to two inter-
locking lines. This means that alternatively both
the interlocking inputs of an alarm channel are
connected to two different interlocking lines, or
the interlocking output and one of the interlock-
ing inputs are connected to two different inter-
locking lines.
When an external interlocking signal is to be
brought into the annunciator unit, one of the
alarm channels can be used as an interlocking
input. In this case the alarm channel may be
given the field contact following visual indica-
tion sequence (S4 = 2) so no audible alarm will
be generated from the channel, see page 29.
Fig. 14. Principles for the interlocking functions of an alarm channel.
SEQUENCE
LOGICS
Reflash B
&
Reflash A
Interlocking output (0)
Acknowledge
Reset
1
Visual indicator
Audible alarm output
Reflash A
interlocking
input (1)
Channel
interlocking
input (2)
Alarm input
(or interlocking input)
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