VDH ALFA 79 User Manual

User manual
ALFA 79
Hygrostat.
VDH doc: 002750
Software: ALFA79
* Installation.
On the topside of the ALFA 79 is shown how the sensor, power supply and relays has to be
connected.
After connecting the ALFA 79 to the power supply, a self test function is started. As this test is
finished the measured humidity appears in the display.
* Control.
The ALFA 79 Hygrostat can be controlled by four push buttons on the front. These keys are:
SET - view / change setpoint and reset alarm.
UP - increase value.
DOWN - decrease value.
%RH - hidden key above SET key and behind %RH symbol.
* View setpoint.
By pushing the SET key the setpoint appears in the display. The decimal point of the last display
starts blinking to indicate this. After a few seconds after releasing the SET key the setpoint
disappears and the measured temperature is shown again.
* Changing setpoint.
Push the SET key and the setpoint appears in the display. Release the SET key. Now push the
SET key again together with the UP or DOWN keys to change the setpoint. After a few seconds
after releasing the SET key the setpoint disappears and the measured temperature is shown
again.
* Status of the Relays.
By pushing the hidden °C key the display shows the status of the relays. Each display segment
shows the status of the relay output, showing 0= off and 1=on. The code 110 means relay 1 and
relay 2 are on and relay 3 is off.
* Setting internal parameters.
Next to the adjustment of the setpoint, some internal settings are possible like differentials,
sensor-adjustments, setpoint-range and function of the Hygrostat.
By pushing the DOWN key for more than 10 seconds, you enter the 'internal program-ming
menu'.
In the left display the upper and the lower segments 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 and DOWN keys allows you to change the value of this parameter.
If after 20 seconds no key is pushed, the ALFA 79 changes to it's normal operation mode.
Version: v1.0
File: Do002750.WP8
1
Datum: 03-01-2001
Range: 0/+100%RH