VDH ALFA-45A User manual

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CPU-unit SUPPLY-unit
User manual ALFA-45A
Cool/Defrost thermostat
with Fan control and
Watch Alarm.
VDH doc. 011524 Version: v1.2 Datum: 27-10-2005
Software: ALFA 45A Doc: Do011524.wpd Range: -50/+50C, per 1C
*Installation.
The ALFA-45A consist of two parts, a Supply-unit for rail-mounting and a CPU-unit for front-mounting
(with operation buttons, display and alarm relay). These two units are connected with each other by an
cable with 8-pole data-connector.
On the front of the ALFA-45A Modulbox supply-unit is shown how sensors, power supply and relay
are to be connected. The watch alarm relay with C/NC contact is to be connected on the CPU-unit.
After connecting the ALFA-45A to the power supply, a self test is started. As this test is finished the
measured temperature of the product-sensor appears in the display.
The Supply-unit has three relay outputs, one for the compressor, one for the fan and one for defrost.
The compressor-relay and the defrost-relay got there own led-indication in the display.
*Control.
The ALFA-45A thermostat can be controlled by three pushbuttons on the front. These keys are:
SET - view / change of settings.
UP - increase of settings.
DOWN - decrease of settings.

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*Viewing setpoint.
By pushing the SET key the setpoint appears in the display. The led ‘set’ starts blinking. A few seconds
after releasing the SET key the setpoint disappears and the measured product temperature is shown
in the display.
*Changing setpoint.
Push the SET key and the setpoint appears in the display. Release the SET key. Now push the SET
key again and together with the UP or DOWN keys the setpoint can be changed. A few seconds afer
releasing the keys the measured product temperature is shown again in the display.
*Manual starting/stopping of defrost.
The defrost cycle is automatic started and stopped. These defrost settings thru internal parameters.
At active defrost the led 'defrost' is on.
Stop defrost:
If there is a defrost cycle, the defrost can by manually stopped by pushing the UP key and than the
SET key, while the UP key is hold.
Start defrost:
If there is no defrost cycle, the defrost can be started manually by pushing the UP key and than the
SET key, while the UP key is hold.
*Setting internal parameters.
Next to the adjustment of the setpoint, some internal settings are possible like differential, sensor-
offset, setpoint range and the defrost function.
By pushing the DOWN key more than 10 seconds, you 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 and DOWN keys allows you to change the value of this parameter.
If after 20 seconds no key is pushed, the ALFA(NET)-45A changes to it's normal operation mode.

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*Parameters ALFA(NET)-45A.
PARA-
METER
DESCRIPTION PARAMETER RANGE STANDARD
VALUE
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
Switching differential
Minimum temperature alarm
Maximum temperature alarm
Offset product sensor
Compressor start-up protection
0 = start-up delay in sec.
1 = start-up delay in min.
2 = delay between switch off and
switch on in min.
3 = delay between switch on and
switch on in min.
Compressor start-up time
belonging to parameter 05
Defrost interval
Maximum defrost time
End of defrost temperature
Fan on temperature (P20=1)
Fan delay time (P20=1)
Drain time in min.
Switching differential fan (P19=1)
Defrost delay after power failure
when parameter P26=1
Startup delay after power failure
Offset defrost sensor
Fan-off delay if parameter P22=1
Alarm delay
Readout defrost sensor
1..15C
-50..+50C
-50..+50C
-15..+15C
0..3
0..99
1..99 hrs.
0..99 min.
-99..+99C
-99.+99C
0..99 min.
0..99 min.
0..99C
0..99 min.
0..99 min.
-15..+15C
0..99 min.
0..99 min.
temp. in C
3
-50
+50
0
0
10
12
15
2
2
0
0
2
0
0
0
0
0
-
Following parameter only
Yes or No selection
0 = No
1 = Yes
20
21
22
23
24
25
26
27
Fan switch differential active
Fan off while defrost active
Compressor on at defrost
Compressor off -> Fan off
Compressor on at product sensor
failure
Defrost cycle time based on
compressor running time
Temperature display locked
during defrost cycle
Start with defrost after power
failure
0..1
0..1
0..1
0..1
0..1
0..1
0..1
0..1
0
0
0
0
0
0
0
0

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*Compressor control.
The compressor relay activates when the product sensor measures a higher temperature than the
setpoint + switching differential (parameter 1), and deactivates when the temperature descents below
setpoint.
There are 4 different modes off delay on the compressor possible with parameter 05 as shown below;
Parameter 05 = 0 :
The compressor relay has a start-up delay of "parameter 6" seconds.
Parameter 05 = 1:
The compressor relay has a start-up delay of "parameter 6" minutes.
Parameter 05 = 2 :
After switching off the compressor waits at least "parameter 6" minutes before switching on
again.
Parameter 05 = 3 :
In between the switching-on points the compressor waits at least "parameter 6" minutes.
Next options for Compressor control are available.
Parameter 15 :
A compressor on delay after power failure of "parameter 15" minutes.
Parameter 24 =1:
The compressor relay activates at product sensor failure.
* Fan control.
The ALFA(NET)-45A has several parameters for fan control. Normally the fan is always active, accept
for one of the following parameters is set to 1, the fan can be stopped.
Parameter 20 = 1 (Fan switch differential active):
The fan is only active when the defrost temperature is "parameter 13" C lower then the
measurement of the product temperature. As there are no further conditions to switch the fan
off. (e.g. Parameter 13 = 2C and the product sensor measures 10C, than the fan is only active
as the defrost sensor measures 10-2=8C or less.)
Parameter 21 = 1 (Fan off on defrost cycle):
The fan is switched off during defrost and to prevent blowing in hot air in the cabin after defrost
and the dripping-off time, there are two conditions which can be set;
1: The fan is blocked until the defrost sensor measures a temperature lower than the
temperature setting of parameter 10.
2: The fan is blocked until the defrost-delay-time of parameter 11 has stopped. Unless the
defrost sensor has reached the temperature setting of parameter 10. When the defrost
sensor is broken (Failure E2) the ALFA(NET)-45A runs down the entire time of parameter
11.
Parameter 23 = 1 (Compressor off -> Fan off):
The fan deactivates as the compressor deactivates, with a delay of "parameter 17" minutes.
Provided that there are no other conditions to deactivates the fan.

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*Defrost control.
The automatic defrost is started by the defrost cycle time (P07) and stopped by the maximum defrost
time (P08) or sooner by reaching the maximum defrost temperature (P09). Further has the
ALFA(NET)-45A additional parameters to control defrost;
Parameter 25 = 0:
Function defrost with a fixed defrost cycle time.
With parameter 7 as the chosen cycle time.
Parameter 25 = 1:
Function defrost based on total compressor running hours.
The defrost is started when the compressor has run for parameter 7 hours after the last defrost.
Parameter 26 = 1:
The temperature readout on the display is locked during defrost cycle.
Parameter 27 = 1:
After power-up the ALFA(NET)-45A starts with defrost after running thru the defrost delay time
of parameter 14. While running down the delay the ALFA(NET)-45A can cool, after this delay
the defrost is started.
Parameter 22 = 1:
On hot gas systems the compressor is switched on during defrost. After defrost the dripping-off
time of parameter 12 is started. During this time the defrost and compressor relay are
deactivated, so the condenser can drip off it’s water.
*Sensor adjustment.
The product sensor (Temp.) can be adjusted by using the Offset product sensor parameter 04.
The defrost sensor (Defr.) can be adjusted by using the Offset defrost sensor parameter 16.
For readout of the defrost sensor on the display use parameter 19.
Indicates a sensor e.g. 2C to much, the according Sensor Offset has to de decreased with 2C.

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*Alarms.
In the display of the ALFA(NET)-45A the following error messages can appear:
E1 - Product sensor error Fatal error, display shows 'E1' and all relays are
deactivated, accept when parameter 24 is 1, then the
compressor and fan are activated as needed.
E2 - Defrost sensor error Non fatal error, the ALFA(NET)-45A go’s on regulating and
the display shows 'E2'.
Solution for E1 and/or E2:- Check if the sensor is connected correctly.
- Check the according sensor (1000/25C).
- Replace according sensor.
EE - Settings are lost Fatal error, settings are lost and display shows 'EE'.
Solution for EE:- Reprogram the settings.
* Alarm Function.
The ALFA(NET)-45A has a minimum alarm (P02) setting and a maximum alarm (P03) setting.
When the temperature is beyond these limits the display shows E3 (maximum alarm) or E4 (minimum
alarm) immediately. The alarm delay (P18) is also started and as the alarm is still on after the delay,
the alarm relay will be deactivated (C/NC contact is closed). Normally (no alarm and power on
controller) the alarm relay is activated (C/NC contact is open). The alarm will not be stored.

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* Technical details.
Types : ALFA-45A Cool/Defrost Thermostat with fan control
ALFANET-45A Cool/Defrost Thermostat with fan control and
RS485-network connection
CPU-unit of the ALFA(NET)-45A
Range : -50/+50C, readout per 1C
Display : 3-digit 7-segment display
Control : pushbuttons on the front.
Status LEDs : 1xLED 'compr.', 1xLED 'set' and 1xLED 'defrost'
Alarm-relay : SPST 250/8A (C-NC) (cos phi=1) Relay normally active,
the C/NC contact is open and at alarm the C/NC contact is closed.
Front : Polycarbonate
Sizes CPU-unit : 35 x 77 x 71,5mm (hwd)
Panel cutout CPU-unit : 28 x 70mm (hw)
SUPPLY-unit of the ALFA-45A
Supply : 230 Vac 50/60Hz
Max. used power : 6,2 VA
Fuse : No internal fuse present
Product sensor : SM 811/2m.
Defrost sensor : SM 811/2m.
Relay Compressor : SPST 250V/ 16A(C-NO) (cos phi=1)
Relay Defrost : SPST 250V/8A(C-NO) (cos phi=1)
Relay Fan : SPST 250V/8A(C-NO) (cos phi=1)
Sizes Supply-unit : 80x70x85mm (hwd) for rail mounting
Operation temperature : 0/+50C
Operation rel. humidity : 10/90 %RH not condensing
Ventilation : Keep ventilation holes open
- Provided with memory protection during power failure.
- Connection with screw terminals.
- Equipped with self test function and sensor failure detection.
- Special version on request available.
*Address.
VDH Products BV Tel: [phone]
Produktieweg 1 Fax: [phone]
9301 ZS Roden Email: [e-mail]
The Netherlands Internet: www.vdhproducts.nl

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*Dimensions CPU-unit. *Dimensions SUPPLY-unit.
*Connections drawing 010061w1.