VDH ALFA 51 PI User manual

Description: Alfa(net) 51 PI -50/+50°C Pages: 8 Doc.no: 180142
Type: Manual By: BVDB Doc.Version: 1.1
File: Do180142 ALFANET 51 PI 6M -
50_+50grC Flash V11 EN.docx
Signed: Date: 26-10-2021
VDH Products BV
Software
15112
3
SW.Version
V3.0
1
Manual ALFA(NET) 71 PI
-50/+50°C
1Function
The ALFA(NET) 51 PI is a DIN-rail mounting thermostat-
unit, with an analog 0-10Vdc PI-output, selectable for
function: Cool and/or Heat.
The thermostat has also three relays outputs selectable for function cooling, heating or alarm. The
temperature is being measured by an SM811 2-Wire temperature sensor. The range of the
thermostat is -50/+50°C
The ALFANET 51 PI is provided with an RS-485 network connection and can be readout or set by an
PC with the ALFANET program connected thru an ALFANET PC-Interface.
2Installation
On the connection diagram of the ALFA(NET) 51 PI is shown how the sensors, analogue output, power
supply, relays and optional network are to be connected. After connecting the ALFA(NET) 51 PI to the
power supply, a self-test function is started. As this test is finished, the measured temperature
appears in the display.
3Control
The ALFA(NET) 51 PI thermostat can be controlled by four pushbutton on the front. These keys are;
SET - view / change set value and reset alarm.
∏ UP - increase set value.
π DOWN - decrease set value.
MODE - relay status key.
4Viewing setpoint
By pushing the SET key the setpoint appears in the display. The decimal point of the last display starts
blinking. A few seconds after releasing the SET key the setpoint disappears and the measured temperature is
shown again in the display.

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5Changing 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. A few seconds after releasing
the keys the measured temperature shows again in the display.
6Viewing/adjusting min./max. -output
Adjusting the minimum and maximum control value (PI) is only possible when the parameter Apply
minimum and maximum control value (P45) is set to 1
By pressing the SET key the setpoint appears in the display.
Only at Parameter P45=1;
Pressing the SET key again displays the minimum control value (P42) in percentages, this can
now be adjusted with the UP and DOWN keys after releasing the SET key.
Pressing the SET key again displays the maximum control value (P43) in percentages, which can
now be adjusted with the UP and DOWN keys after releasing the SET key.
By pressing the SET key again, the measured temperature is shown in the display again.
About 15 seconds after releasing the keys, the measured temperature is shown in the display.
7Status 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 0=off and 1=on. The code 110 means relay 1 and 2 are on
and relay 3 is off.
8Viewing the PI-output percentage
Push the MODE and UP keys simultaneously. Now the PI-output percentage is shown in the display.
9Adjustment sensor
The temperature sensor can be adjusted by using the Sensor Offset parameter 05.
Indicates the Sensor e.g. 2,0°C too much, the Sensor Offset has to be decreased with 2,0°C.

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10 Error messages
In the display of the ALFA(NET) 51 PI the following error messages can appear:
Lo1 - Minimum alarm. Solution E1:
Hi1 - Maximum alarm. - Check if the sensor is connected correctly.
E1 - Sensor-1 failure. - Check sensor (1000Ω/25°C).
- Replace sensor.
-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 resetted by pushing the SET key.
The function of this key depends on parameter P37.
11 Technical data
Type ALFA 51 PI -50/+50°C or
ALFANET 51 PI -50/+50°C
Range -50/+50°C readout per 0,1°C
Supply 100…240 Vac 50/60Hz max. 10VA
Display 3-digit 7-segment LED display
Sensor
SM 811 2
-
Wire
PTC 1000
Ω
/25°C
Relays Ry1 = SPST (NO) 250V/8A cosphi=1 or 250V/5A cosphi=0.4
Ry2 = SPST (NO) 250V/8A cosphi=1 or 250V/5A cosphi=0.4
Ry3 = SPDT (NO/NC) 250V/8A cosphi=1 or 250V/5A cosphi=0.4
Relays have one common (C)
Analogue output 0-10Vdc PI-output Rload = min. 10KOhm
Communication RS-485 Network Twisted-pair shielded
only at ALFANET A, B, 0V (Twist A and B)
Connect according to newest norm ANSI/TIA/EIA-485-A-98
Control By four push buttons on the front
Front Polycarbonate
Dimensions 35 x 77 x 71,5 mm (H x W x D)
Panel cut out 28 x 70 mm (H x W) front mounting
- Provided with memory protection during power failure.
- Connection with screw terminals.
- Equipped with senor failure detection.
- Special versions are on request available.

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12 Setting internal parameters
Next to the adjustment of the setpoint, internal settings can be made like differential, sensor offset,
setpoint range and the functions of the thermostat.
Push the DOWN key for more than 10 seconds, to enter the 'Internal Programming Menu'. In the left
display the upper- and lower-segment are blinking.
With the UP and DOWN keys the required parameter can be selected (see the parameter table).
If the required parameter is selected, the value can be read-out by pushing the SET key. Pushing the
UP or DOWN key to change the value of this parameter.
If after 20 seconds no key is pushed, the ALFA(NET) 51 PI changes to the normal operation mode.
12.1 Parameters ALFA(NET) 51 PI
Para-
meter
Description Parameter Range Default
value
01 Function Relay 1 1 = Cool
2 = Heat
3 = Alarm
1..3 1
02 Function Relay 2 same as parm. P01 1..3 2
03 Function Relay 3 same as parm. P01 1..3 3
04 Function PI-output 1 = Cool
2 = Heat
3 = Cool and Heat
1..3 1
05 Offset temperature sensor (Calibration) -15 .. +15.0°C 0.0
06 Offset PI -15 .. +15.0°C 0.0
07 P-band setting 0.0 .. 20.0°C 5.0
08 I-time setting (I-action not active at
P08 = 0 of P04 = 3)
0 .. 99 Minutes 0 (= off)
10 Switch-on stage two 0 = Temp, 1 = Time 0
11 Switch-on stage three 0 = Temp, 1 =Time 0
12 Switch-on delay stage two 0 .. 99 Minutes 0
13 Switch-on delay stage three 0 .. 99 Minutes 0
14 Switching differential relay 1 * 0.1 .. 15.0°C 0.5
15 Switching offset relay 1 * -15.0 .. +15.0°C 0.0
16 Switching differential relay 2 * 0.1 .. 15.0°C 0.5
17 Switching offset relay 2 * -15 .. +15.0°C 0.0
18 Switching differential relay 3 * 0.1 .. 15.0°C 0.5
19 Switching offset relay 3 * -15 .. +15.0°C 0.0
20 Switch-on delay cooling 0 .. 99 0
21 Switch-off delay cooling 0 .. 99 0
22 Parameter 20/21 in seconds or minutes 0 = Sec, 1=Min 0
23 Minimum on-time cooling 0 .. 99 Minutes 0
24 Minimum off-time cooling 0 .. 99 Minutes 0
25 Minimum adjustable setpoint -50 .. +50.0°C -50.0
26 Maximum adjustable setpoint -50 .. +50.0°C +50.0
27 Readout in whole degrees 0 = No, 1 =Yes 0

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Para-
meter
Description Parameter Range Default
value
30 Alarm type 0 = None
1 = Absolute
2 = Relative
0 .. 2 1
31 Minimum alarm setpoint -50 .. +50.0°C -50.0
32 Maximum alarm setpoint -50 .. +50.0°C +50.0
33 Time delay minimum alarm 0 .. 99 Minutes 0
34 Time delay maximum alarm 0 .. 99 Minutes 0
35 Function alarm relay 0 = Watch alarm
1 = Control alarm
0 .. 1 0
36 Reset alarm relay after recovering alarm 0 = No, 1 =Yes 0
37 Reset alarm relay after manual reset 0 = No, 1 =Yes 0
40 Start-up delay after power failure * 0 .. 99 Minutes 0
41 Forced relay function at sensor failure
0 = None
1 = Cool
2 = Heat
0 .. 2 0
42
43
45
Minimum control value
Maximum control value
Apply minimum and maximum control value
0 .. 100%
0 .. 100%
0 = No, 1 =Yes
0
100
0
90 Network number (only at ALFANET) 1..250 1
95 Software version - -
96 Production year - -
97 Production week - -
98 Serial number (x1000) - -
99 Serial number (units) - -
*) These parameters are only applied to relays with function cool or heat.

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13 Function diagram

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14 Connections

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15 Dimensions
16 Address
VDH Products B.V. Tel.:
+31 (0)50 – 30 28 900
Productieweg 1 Fax.: +31 (0)50 – 30 28 980
9301 ZS Roden Email: [e-mail]
The Netherlands Internet: www.vdhproducts.nl