2. Alarms and shutdowns
2.1. Analog alarms and shutdowns
2.1.1 Introduction
Shutdown and alarm limits can be set separately as described in subsection 1.2.6. Changing
set values. Unisab III does not check whether shutdown and alarm limits have been inter-
changed by mistake (e.g. if alarm limit for high discharge pressure is set higher than the
shutdown limit). Consequently, always check the settings when making adjustments. If an
alarm limit is exceeded, the light diode above the
key will flash yellow quickly, and the
alarm relay will be activated. The reason for the alarm is shown in the Alarm picture. If there
is more than one alarm this is indicated in the top bar.
Note that in case of alarm, a limiter might be active as described in section 3.2. Limiting func-
tions. When the alarm disappears, it is automatically acknowledged and removed from the
Alarm picture and the alarm relay returns to its normal position.
If a shutdown limit is exceeded, the compressor immediately stops and the light diode above
the key flashes red quickly. The Shutdown picture shows the reason for the shutdown and
at the same time the shutdown relay changes its position.
The shutdown relay works by connecting the shutdown/common switch during shutdown and
disconnecting it once the shutdown has been reset. The Shutdown picture shows the exact
time of the shutdown. See also 5.2. Diagnosis. To reset the shutdown, press the
F4
/RESET
key. The alarm and shutdown relays will then return to their normal positions. However, if the
shutdown value is still outside the limit, the light diode will continue to flash red, but slowly.
When the situation has returned to normal, the
F4
/RESET key must be pressed once more.
The set values for high and low shutdowns as well as the factory values are stated in the fol-
lowing tables (Table 8-Table 15) followed by explanatory notes.
Alarms and shutdowns
36/319
Engineering manual - Unisab III 1.10
001930 en 2014.09
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