2
*Actions of the alarm functions.
TheALFA(NET) 33 alarm thermostathasaminimumalarm andamaximumalarmboth with thereown
set point. It is possible to adjust two different kinds of alarms (PARAMETER 27) namely:
Fail safe alarm relay normally activated, with alarm it falls off and the led 'alarm' is on. So on
power failure the alarm relay also falls off. or a
Control alarm relay normally not activated, with alarm the relay will be activated and the led
'alarm' will be on.
PARAMETER 28 can be used to adjust an auto reset alarm or a hold alarm, after temperature
recovers.
It is also possible to give both set points their own offset and differential (see function diagram). For
each alarm an alarm-delaytime (PARAMETER 23 and 24) canbe set. Whenan alarm occurs, the led
'alarm' first starts to blink. If the temperature will recover within the delay time, no alarm occurs. If an
alarm will comethroughafterthe delaytimetheled 'alarm'is oncontinuouslyandthedisplayalternates
between the temperature and 'H' for high-alarm (max.) or 'L' for low-alarm (min.) to indicate the alarm.
To reset an alarm, press the SET key.
*Setting internal parameters.
Next to the adjustment of the set point, some internal settings are possible like differential, sensor-
offset, setpoint range.
By pushing the DOWN key for more than 10 seconds, you enter the 'internal programming menu'. In
the left display the upper- and lower-segment are blinking. Withthe UP and DOWN keys the required
parameter can be selected (see the parameter table). If the required parameter is selected, the value
can be read-out by pushing the SET key. Pushing the UP or DOWN keys, allows you to change the
value of this parameter. If no keyis pushed for 20 seconds, the ALFA(NET) 33 changes to it's normal
operation mode.
*Sensor adjustment.
The sensor can be adjusted by using the Sensor Offset (parameter 04). Indicates the ALFA(NET) 33
e.g. 2C too much, the Sensor Offset has to de decreased by 2C.
*Error messages.
In the display of the ALFA(NET) 33 the following error messages can appear:
E1 - Sensor broken. Solution:
- Check if the sensor is connected correctly.
- Check the sensor (1000at 0C).
- Replace the sensor.
EE - Settings are lost. Solution:
- Re programme the settings.
-L- - In case of sensor short-circuit the display alternates between error-code E1
and -L-, as indication for a short-circuit sensor.
-H- - In case of open-circuit sensor the display alternates between error-code E1
and -H-, as indication for a open circuit sensor.
