2
*Setting internal parameters.
Next to the adjustment of the setpoint, internal settings can be made like differential, sensor-offset,
setpoint range and the functions of the thermostat.
Push the DOWN key more than 10 seconds, to enter the 'Internal Programming Menu'. In the left
display the upper and lower segment are blinking. Over the UP and DOWN keys the required
parameter can be selected (see table for the parameters).
If the required parameter is selected, the value can be read-out by pushing the SET key. Pushing
the UP or DOWN key to change the value of this parameter.
If after 20 seconds no key is pushed, the ALFA 71 MOD changes to the normal operation mode.*
Adjustment sensors.
The temperature sensor can be adjusted by using the Sensor Offset parameter 05.
Indicates the Sensor e.g. 2C to much, the Sensor Offset has to be decreased with 2C.
*Error messages.
In the display of the ALFA 71 MOD the following error messages can appear:
LO - Minimum alarm. Solution E1:
HI - Maximum alarm. - Check if the sensor is connected correctly.
E1 - Sensor-1 failure. - Check sensor (1000at 25C).
- Replace sensor.
EEE - Settings are lost. Solution EEE:
- Reprogram the settings.
-L- - In case of sensor short-circuit the display alternates between error-code E.. and -L-,
as indication for a short-circuit sensor.
-H- - In case of open-circuit sensor the display alternates between error-code E.. and -H-,
as indication for a open circuit sensor.
Reset Alarm. When a error-messages appears it can be resetted by pushing the SET key.
The function of this key depends on parameter P37.
*Technical details.
Type : ALFA 71 MOD Thermostat
Range : 0/+100,0C, per 0,1C
Supply : 12Vac 50/60Hz (-5/+10%)
Display : 3-digit 7-segment display
Relays : Ry1= Open SPST(NO)250V/8A (cos =1) of 250V/5A (cos =0.4)
Ry2= Close SPST(NO)250V/8A (cos =1) of 250V/5A (cos =0.4)
Ry3= Alarm SPDT(NO/NC)250V/8A (cos =1) of 250V/5A (cos
=0.4)
Relays have one common (C).
Control : By push buttons on front.
Front : Polycarbonate IP65
Sensor : SM 811/2m (PTC 1000/25C).
Analog output : 0..10 Vdc PI output (cool or heat)
Dimensions : 35 x 77 x 71,5mm (HWD)
Panel cutout : 28 x 70mm (HW)
Accuracy : ± 0,5% of the range.
- Provided with memory protection during power failure.
- Connections with screw terminals on the back side.
- Equipped with sensor failure detection.
- Special versions on request available.
