VDH ALFA 79 User manual

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User manual
ALFA 79
Hygrostat.
VDH doc: 002750 Version: v1.0 Datum: 03-01-2001
Software: ALFA79 File: Do002750.WP8 Range: 0/+100%RH
*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.

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*Sensor adjustment.
The humidity-sensor can be adjusted by using the Offset Humidity sensor (parameter 05).
Indicates the ALFA 79 e.g. 2% too much, than the Offset Humidity sensor (parameter 05) has to
be decreased with 2%.
*Error messages.
In the display of the ALFA 79 the following error messages can appear:
rLO - Minimum RH alarm. Solution E1:
rHI - Maximum RH alarm. - Check if sensor is connected correctly.
E1 - RH sensor failure.* - Check RH-signal. (0/+100%RH=0/+1Vdc)
- Replace sensor.
EE - Settings are lost. Solution EE:
- 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 reset by pushing the SET key. The function of this key
depends on parameter P37.
* Technical details.
Type : ALFA 79 Hygrostat.
Range : 0/+100%RH read-out per 1%RH
Read out : 3-digit 7-segments display
Status LEDs : LED 'SET' and LED 'RH'
Supply : 12 Vac 50/60Hz (-5/+10%).
Relays : Ry1= SPST(NO) 250V/8A (cos φ=1) of 250V/5A (cos φ=0.4)
Ry2= SPST(NO) 250V/8A (cos φ=1) of 250V/5A (cos φ=0.4)
Ry3= SPDT(NO/NC) 250V/8A (cos φ=1) of 250V/5A (cos φ=0.4)
The three relays have one common (C).
Control : Thru pushbuttons on front.
Front : Polycarbonate.
Sensor : RH 95-2 (+12Vdc; 0/+100%RH = 0/+1Vdc)
Dimensions : 35 x 77 x 71,5mm (HWD).
Panel-cutout : 29 x 71mm (HW).
Accuracy : ± 0,5% of range.
- Provided with memory protection during power failure.
- Equipped with self-test function and sensor-failure detection.
- Connection with screw-terminals.
- Special version on request available.

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*Parameters ALFA 79
Para-
meter Description Parameter Range Default Value
01
02
03
Function Relays 1
Function Relays 2
Function Relays 3
1=Humidify
2=Dehumidify
3=Alarm
1=Humidify
2=Dehumidify
3=Alarm
1=Humidify
2=Dehumidify
3=Alarm
1
2
3
05 Offset Humidity sensor -15..+15%RH 0
10
11
12
13
14
15
Switching differential relay 1
Switching offset relay 1
Switching differential relay 2
Switching offset relay 2
Switching differential relay 3
Switching offset relay 3
1..15%RH
-15..+15%RH
1..15%RH
-15..+15%RH
1..15%RH
-15..+15%RH
1
0
1
0
1
0
20
21 Minimum setpoint Maximum setpoint 0..100%RH 0..100%RH 0 100
30
31
32
33
34
35
36
37
Alarm mode
Minimum alarm setpoint
Maximum alarm setpoint
Time-delay minimum alarm
Time-delay maximum alarm
Function alarm relay
Auto reset alarm after failure
recovering
Manual reset alarm relay with set key
0= None
1= Absolute
2= Relative
0..100%RH
0..100%RH
0..99 min.
0..99 min.
0= watchdog al.
1= regulated al.
0= No
1= Yes
0= No
1= Yes
1
0
100
0
0
0
0
0
40
41 Control-delay after power failure Forced relay function at sensor failure 0..99 min. 0= None
1= Humidify
2= Dehumidify
0
0
95
96
97
98
99
Software version
Production year
Production week
Serial number (x1000)
Serial number (units)
0..255
00..99
1..52
0..255
0..999
0
0
1
0
0
(c) VDH Products BV

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*Dimensions.
*Connections.
*Address.
VDH Products BV Tel: [phone]
Produktieweg 1 Fax: [phone]
9301 ZS Roden Email: [email protected]
The Netherlands Internet: www.vdhproducts.nl