DCU 205 User’s Manual
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5.
A
LARM CENTRE
5.1.
In general
The Control Unit has a total of 9 alarms. Three of these alarms are
internally generated by the Control Unit, and the remaining 6 alarms are
based on normally closed contacts from the controlled system, i.e., an
open contact will set off an alarm. The three internal alarms are:
•
Supply voltage low
•
Automatic start failed, and
•
Speed sensor failure
An activated alarm is indicated by its
flashing lamp on the front panel. At the
same time, the alarm will start the siren and
activate the common alarm output relay.
The siren can be silenced by pressing the
Siren Off
button (marked with a symbol)
located on the front panel.
The alarms are reset by pressing the
RESET button. The common alarm relay will
return to normal and the flashing lamp will
stop flashing but remain lit. This indicates
that the alarm has been acknowledged but
is still present. The light turns off when the
alarm actually disappears.
Supply voltage low
Alarm is given if the supply voltage drops below 23.5V. Interlocked in
60 sec. and while starting.
Failed automatic start
After 3 failed start attempts AUTOMATIC START FAILED and
COMMON ALARM will appear.
Speed sensor failure
If the alarm is activated while the engine is running, it is either a broken
wire connection or the signal might be too weak. Signal strength can be
measured between wire terminals 3 and 4, and should be at least 2.0VAC.
If the actual alarm has disappeared before it has been acknowledged
(reset), the flashing lamp and the common alarm will remain on until the
RESET button has been pressed. All alarm inputs are delayed by 1.5
seconds.
The LUB. OIL PRESS. LOW and the extra SPARE alarm inputs are
interlocked for 15 seconds after the engine has started, thus these alarms
will not be triggered while the engine is stopped.
