VDH ALFANET 55 RTDF, ALFA 55 RTDF User Manual

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User manual
ALFA 55 RTDF and
ALFANET 55 RTDF

Cool/Defrost
thermostat with
fan-control and
realtime defrost.

VDH doc. 030087 Version: v2.1 Date: 10-03-2008

SW: 992649_ALFA(NET) 55/65/75 RTDF File: Do030087.wpd Range: -50,0/+50,0C pro 1C

* Description.

The ALFA(NET) 55 RTDF is a cool/defrost thermostat for rail-mounting, with various defrost-, and fan-
control settings. The thermostat has 6 Real-Time DeFrost time settings a day available.
The ALFANET 55 RTDF has a RS 485 network connection so it can be read out and adjusted on the
Alfanet.

* Installation.

On the connection diagram of the ALFA(NET) 55 RT DF is shown how the sensor, power supply and
relays has to be connected.
After connecting the ALFA(NET) 55 RTDF to the power supply, a self test function is started. As this
test is finished, the measured temperature of the control-sensor appears in the display.

* Control.

The ALFA(NET) 55 RTDF thermostat can be controlled by four push buttons on the front. These keys
are:

SET - view / change the setpoint.
UP - increase value.
DOWN - decrease value.
MODE - relay status key.

* 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 MODE key, the display shows the status of the relays. Each display segment shows the
status of the relay output, showing =off, =on and on the last segment=natural defrost active.
The code means relay 1(compr.) and 2(fan) are on and relay 3(defr.) is off.

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* Manual starting/stopping of defrost.

The defrost cycle is automatic started and stopped. These defrost settings thru internal parameters.
Stop defrost: If there is a defrost cycle , the defrost can be manually stopped by pushing the UP and

the DOWN key simultaneously.

Start defrost: If there is no defrost cycle , the defrost can be manually started by pushing the UP and

the DOWN key simultaneously.

* Sensor adjustment.

The temperature-sensor can be adjusted by using the Offset control sensor (parameter 05). The
defrost-sensor can be adjusted by using the Offset defrost sensor (parameter 07). For read out of the

defrost sensor on the display use parameter 06 (Only if parameter 08 = 1).
Indicates a sensor e.g. 2C too much, the according Sensor-offset parameter has to be decreased with
2C.

* Error messages.

In the display of the ALFA(NET) 55 RTDF the following error messages can appear:

LO - Minimum alarm Solution E1/E2:
HI - Maximum alarm - Check if sensor is connected correctly.
E1 - Control sensor failure - Check sensor (1000/25C).
E2 - Defrost sensor failure - 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 reset by pushing the SET key. The function

of this key depends on parameter P37.

* Alarm operation.

As a failure or alarm occurs an error message is shown in the display. The ALFA(NET) 55 RTDF
remembers it’s error message, although it is already solved. The error message is resettable with the
SET key.
As if after pressing the SET key (=reset alarm) the alarm still is not solved than the ALFA(NET) 55
RTDF displays the temperature and the error message alternated, is the alarm solved, then the error
message disappears and the temperature is displayed normally.

* Setting internal parameters.

Next to the adjustment of the setpoint, some internal settings are possible like differentials, sensor­adjustments, setpoint-range, compressor-, fan-, defrost- and alarm-settings.
By pushing the DOWN key for more than 10 seconds, you enter the 'internal programming 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(NET) 55 RTDF changes to it’s normal operation mode.

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* Parameters ALFA(NET) 55 RTDF.

Para­meter

Description Parameter Range Default

Value

01
02
03
04
05
06
07
08

Switching differential
Minimum setpoint
Maximum setpoint
Read out above -10C per 1C
Offset Control-sensor
Read out Defrost-sensor
Offset Defrost-sensor
Defrost sensor present

1..15C

-50..+50C

-50..+50C
0=No, 1=Yes

-15..+15C

-

-15..+15C
0=No, 1=Yes

0,5

-50

+50

0

0,0

-

0,0

0

10
11
12
13
14

Start-up delay Cooling
Switch-off delay Cooling
Parameter 10/11 in Seconds or Minutes
Minimum on-time Cooling
Minimum off-time Cooling

0..99

0..99
0=Sec. 1=Min.

0..99 Minutes

0..99 Minutes

0
0
0
0
0

20
21
22
23
24

25
26
27

Switching differential Fan active
Switching differential Fan
Fan off as Compressor is off
Switch-off delay Fan
Defrost mode 0=only fan-relay,
1=only defrost-relay
Switch-on delay-temp. fan after defrost
Switch-on delay-time fan after defrost
Dripoff-time

0=No, 1=Yes

0..+50C
0=No, 1=Yes

0..99 Minutes
0 = Natural
1 = Hotgas / Elec.

-50..+50C

0..99 Minutes

0..99 Minutes

0

2,0

0
0
0

2,0

0
0

30
31
32
33
34
35
36
37

Defrost-interval-time
Maximum defrost-time
End of defrost temperature
Compressor on while defrosting
Defrosting on compressor-time
Temperature display locked during
defrost cycle
Start with defrost after power-up
Defrost on-delay after power-up

1..99 Hours

0..99 Minutes

-50..+50C
0=No, 1=Yes
0=No, 1=Yes
0=No, 1=Yes
0=No, 1=Yes

0..99 Minutes

12
15

2,0

0
0
0
0
0

40

41
42
43
44
45
46
47

Alarm mode 0 = No alarm

1 = Absolute alarm

2 = Relative alarm
Minimum alarm setpoint
Maximum alarm setpoint
Time-delay maximum alarm
Time-delay minimum alarm
Control-delay after power failure
Compressor on at control-sensor failure
Compressor off at minimum alarm

0..2

-50..+50C

-50..+50C

0..99 Minutes

0..99 Minutes

0..99 Minutes
0=No, 1=Yes
0=No, 1=Yes

1

-50

+50

0
0
0
0
1

50
51
52

Actual realtime (hours)
Actual realtime (minutes)
Time correction (at realtime clock)

0..23 Hours

0..59 Minutes

-99..+99

-

-

0