Special chapter for service technicians
2 --- 7
2.8 ADT
Not all temperature limit settings are adjustable.
Alarm message ADT > > (maximum permissible airend discharge temperature ex-
ceeded)
ADT > 110˚ C The compressor shuts down after 2 seconds.
ADT > 120˚ C The compressor shuts down immediately.
The alarm can be acknowledged when the temperature drops below 105 ˚C.
Alarm message ADT < < (airend discharge temperature below permissible minimum)
The warning message “T” indicates that the operating temperature is below the per-
mitted minimum (---10 ˚ C). Motor starting is inhibited.
The controller can be switched on but the motor start inhibit is only lifted when the
temperature rises above ---10 ˚ C.
Minimum operating temperature monitoring is only active before the motor is started;
no reaction occurs if the temperature falls below ---10 ˚ C while the motor is running.
2.9 Analog Inputs Monitoring
Analog pressure input (4---20mA)
The input current must be in the range
3mA (---1bar) < = le< = 20mA (16 bar)
An alarm is signalled if it moves out of this range.
Analog temperature input (PT100)
An open analog input is recognised by a temperature exceeding the limit of + 150 ˚ C
and a short between analog inputs or to the casing by a drop in temperature below
---46 ˚ C.
Parallel to this, monitoring of open input or short to earth (also resistance breakdown)
is achieved by registration of an error current on AI2 by means of an electronic switch
on the board.
2.10 Internal Temperature Acquisition
The internal temperature of the controller is available to the system as an analog value. An
alarm message is triggered if the temperature exceeds 65 ˚ C. The alarm is cancelled if the
internal temperature falls below 50 ˚ C.
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