VDH ALFANET 55 RTDF, ALFA 55 RTDF User Manual

1

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

Para­meter

Description Parameter Range Default

Value

4

60
61
62
63
64
65
66
67
68
69
70
71
72

Real-time defrost active
Defrost-time 1 (Hours)
Defrost-time 1 (Minutes) steps 10 Min.
Defrost-time 2 (Hours)
Defrost-time 2 (Minutes) steps 10 Min.
Defrost-time 3 (Hours)
Defrost-time 3 (Minutes) steps 10 Min.
Defrost-time 4 (Hours)
Defrost-time 4 (Minutes) steps 10 Min.
Defrost-time 5 (Hours)
Defrost-time 5 (Minutes) steps 10 Min.
Defrost-time 6 (Hours)
Defrost-time 6 (Minutes) steps 10 Min.

0=No, 1=Yes

0..23 / off Hours

0..50 / off Min.

0..23 / off Hours

0..50 / off Min.

0..23 / off Hours

0..50 / off Min.

0..23 / off Hours

0..50 / off Min.

0..23 / off Hours

0..50 / off Min.

0..23 / off Hours

0..50 / off Min.

0
off
off
off
off
off
off
off
off
off
off
off
off

80
81
82
83
84

Night-shift (offset) of Setpoint
Start day (Hours)
Start day (Minutes) step 10 Min.
Start night (Hours)
Start night (Minutes) step 10 Min.

-10.0...10.0C

0..23 / off Hours

0..50 / off Min.

0..23 / off Hours

0..50 / off Min.

0
off
off
off
off

90
95
96
97
98
99

Network number
Software version
Production Year
Production Week
Serial number (x1000)
Serial number (units)

0..255

0..255

00..99

1..52

0..255

0..999

1

-

-

-

-

-

* Fan control.

The ALFA(NET) 55 RTDF 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 21" lower than the measured
product temperature. Fan on : Tdefr.<(Tcontrol-Tfandiff.(P21)) As there are no further
conditions to switch the fan off.

Parameter 25,26 Fan on-delay after defrost:

The fan is switched off during defrost and to prevent blowing in hot air in the cabin after defrost and
the dripping-off time (parameter 27), there are two conditions which can be set;
a: The fan is blocked until the defrost sensor measures a temperature lower than the temperature

setting of parameter 25.

b: The fan is blocked until the defrost-delay-time of parameter 26 has stopped. Unless the defrost

sensor has reached the temperature setting of parameter 25.

Parameter 22 = 1 Compressor off than Fan off:

The fan deactivates as the compressor deactivates, with a delay of "parameter 23" 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 (P30) and stopped by the maximum defrost
time (P31) or sooner by reaching the maximum defrost temperature (P32).
Further has the ALFA(NET) 55 RTDF additional parameters to control defrost;

Parameter 24 Defrost mode:

The ALFA(NET)-55 RTDF has two defrost modes;
P24 = 0 While defrosting only the Fan activates. (Natural defrost).
P24 = 1 While defrosting the relay DEFR. activates. (Hotgas / Electrical defrost).

Parameter 34 = 0 : Defrost at fixed interval time (P60=0).

In this case parameter 30 is the chosen interval time.

Parameter 34 = 1 : Defrost based on total Compressor-time (P60=0).

In this case the Defrost is started as the Compressor has been activated for “parameter 30" hours.

Parameter 60 = 1: Defrost based on Real-time Clock.

In this case the Defrost is started at fixed times, set with parameters P61 until P71.

Parameter 36 = 1 : The ALFA(NET) 55 RTDF starts with Defrost on Power-up.

After Power-up the ALFA(NET) 55 RTDF first starts with a delay of “parameter 37" minutes before
starting Defrost, while in delay the ALFA(NET) 55 RTDF works normally.

Parameter 33 = 1 : Compressor active at Defrost. (P24=1)

For hot-gas Defrost-systems the Compressor needs to be activated while defrosting. After Defrost
the Drip-off -time (parameter 27) starts. During this time the defrost-relay and the compressor are
not active so the Cool-unit can drip off.

* Technical details.

Type : ALFA 55 RTDF Cool/Defrost Thermostat or

ALFANET 55 RTDF Cool/Defrost Thermostat with network

Range : -50/+50C Readout pro 1C
Supply : 230 Vac / 2,5VA 50/60Hz (or else see product sticker)
Relays : The three relays have one common;

Ry-1 Compr. SPST (NO) 250V/8A (cos =1)
Ry-2 Fan SPST (NO) 250V/8A (cos =1)
Ry-3 Defrost SPDT (NO,NC) 250V/8A (cos =1)

Control : Thru pushbuttons on front.
Front : Polycarbonate IP65
Sensors : Control sensor-1 SM 811/2m(PTC 1000/25C)

Defrost sensor-2 SM 811/2m(PTC 1000/25C)

Communication : RS485 network (2xTwisted-pair shielded cable min. 0,5mm2) only at ALFANET

Attention both networkcable ends must be terminated with a 250 Ohm resistor

between Line-A and Line-B.
Dimensions : 90 x 71 x 58mm (hwd)
Panel cutout : 46 x 71mm (hw) at front mounting
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 versions on request available.

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* Dimensions.

7

* Connections.

8

* Function diagram.

* Address.

VDH Products BV Tel: [phone]
Produktieweg 1 Fax: [phone]
9301 ZS Roden Email: [e-mail]
The Netherlands Internet: www.vdhproducts.nl