Velleman-Kit K2649 User manual

THERMOSTAT WITH LCD-DISPLAY
K2649
ILLUSTRATED ASSEMBLY MANUAL H2649IP-1
Total solder points: 166 + 116
Difficulty level: beginner 12345 advanced
Digitalreadoutofbothsetandactual
temperature.

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The very precise digital display of both the set and actual temperature makes this thermostat very easy to
use.
Also very useful is the connecting capability for an 'economy switch': when the contact is closed then the set
temperature is decreased by a number of degrees.
No measuring apparatus is needed for adjustments. Thanks to the wide setting range of both the hysteresis
and the desired temperature, this kit can also be used for a lot more applications than only regulating room
temperature.
Features:
 Wide measuring and regulating range: -50 to +150°C (-60 to +300°).
 Adjustable hysteresis: 0,2°C (0,4°F) to 10°C (18°F).
 Resolution of the display: 0,1°C or 1°F.
 Can be set for degrees Celsius or Fahrenheit.
 Connecting capability for economy switch.
Specifications:
 Power supply and transformer included.
 Mains voltage: 220/240V (110 for USA and Canada).
 Relay output: 240V, 3A max.
 Dimensions: 123.5x62x65 mm.
Features & Specifications

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Assembly hints
1. Assembly (Skipping this can lead to troubles ! )
Ok, so we have your attention. These hints will help you to make this project successful. Read them carefully.
1.1 Make sure you have the right tools:
• A good quality soldering iron (25-40W) with a small tip.
• Wipe it oftenon a wet sponge or cloth, to keep it clean; thenapply solder to the tip, togive it awet look. This is called ‘thinning’ and will
protect the tip,and enables youto make goodconnections. When solder rollsoff the tip, it needs cleaning.
• Thin raisin-core solder. Do not use any flux or grease.
• A diagonal cutter to trim excess wires. To avoid injury when cutting excess leads, hold the lead so they
cannot fly towards the eyes.
• Needle nose pliers, for bending leads, or to hold components in place.
• Small blade and Phillips screwdrivers. A basic range is fine.
For some projects, a basic multi-meter is required, or might be handy
1.2 Assembly Hints :
⇒ Make sure the skill level matches your experience, to avoid disappointments.
⇒ Follow the instructions carefully. Read and understand the entire step before you perform each operation.
⇒ Perform the assembly in the correct order as stated in this manual
⇒ Position all parts on the PCB (Printed Circuit Board) as shown on the drawings.
⇒ Values on the circuit diagram are subject to changes.
⇒ Values in this assembly guide are correct*
⇒ Use the check-boxes to mark your progress.
⇒ Please read the included information on safety and customer service
* Typographical inaccuracies excluded. Always look for possible last minute manual updates, indicated as ‘NOTE’ on a separate leaflet.
0.000

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Assembly hints
1.3 Soldering Hints :
1- Mount the component against the PCB surface and carefully solder the leads
2- Make sure the solder joints are cone-shaped and shiny
3- Trim excess leads as close as possible to the solder joint
REMOVE THEM FROM THE TAPE ONE AT A TIME !
AXIAL COMPONENTS ARE TAPED IN THE CORRECT
MOUNTING SEQUENCE !
You will find the colour code for the resistances and the LEDs in the HALG
(general manual) and on our website: http://www.velleman.be/common/service.aspx

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 R20 : 10K (1 - 0 - 0 - 2 - 1)
 R21 : 10K (1 - 0 - 0 - 2 - 1)
 R22 : 47K (4 - 7 - 0 - 2 - 1)
 R23 : 47K (4 - 7 - 0 - 2 - 1)
5. Metal film resistors
R...
Construction
 IC2 : 14P
6. IC socket, Watch the
position of the notch !
 ZD1 : 8V2 - 500mW.
2. Zenerdiode. Watch the
polarity !
ZD...
CATHODE
A. POWER SUPPLY MODE ‘P2649V’
 D5 : 1N4148
1. Diode. Watch the polarity !
D...
CATHODE
 D1 : 1N4007
 D2 : 1N4007
 D3 : 1N4007
 D4 : 1N4007
3. Diodes. Watch the polarity !
D...
CATHODE
 R1 : 560 (5 - 6 - 1 - B)
 R3 : 100K (1 - 0 - 4 - B)
 R4 : 100K (1 - 0 - 4 - B)
 R6 : 100K (1 - 0 - 4 - B)
 R15 : 220K (2 - 2 - 4 - B)
 R16 : 220K (2 - 2 - 4 - B)
 R17 : 560K (5 - 6 - 4 - B)
 R18 : 560K (5 - 6 - 4 - B)
 R26 : 820 (8 - 2 - 1 - B)
 R27 : 1K (1 - 0 - 2 - B)
 R28 : 10K (1 - 0 - 3 - B)
 R29 : 82 (8 - 2 - 0 - B)
 R34 : 6K8 (6 - 8 - 2 - B)
 R35 : 5M6 (5 - 6 - 5 - B
4. Resistors
R...

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Construction
 C3 : 100nF (104)
7. Ceramic capacitor.
 T1 : BC557B
8. Transistor.
 J1 : Mains.
 J4 : “ES” Economy switch.
 J2 :
 For heaters use the contacts :
‘C’ & ‘NO’.
 For coolers use the contacts :
‘C’ & ‘NC’.
 The connection side of the
connectors must point to the
PCB-opening!
12. Terminal blocks.
 RV4 :10K
9. Horizontal trimmer
R...
 C10 : 1µF/63V
10. Capacitor
 RV5 :4M7 (5M)
11. Vertical trimmer
RV...

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 RY1 : VR15M121C
15. Relay
 IC2 : LM324
18. IC. Watch the position of
the notch!
 C2 : 100µF
C...
Construction
 F1 : 100mA
(slow)
14. Fuse holder & Fuse
F...
 C1 : 1000µF
 TRAFO1 : 12V - 0,1A
17. Transformer
TRANSFORMER
220V 12V
13. Electrolytic Capacitor.
Watch the polarity !
C...
16. Electrolytic Capacitor.
Watch the polarity !
 J3 : FC8 “9 wire”
19. Flat cable
 Small hysteresis
If you desire a small hysteresis
(adjustable from 0,2 to 1°C or
from 0,4 to 4°F), then fit for R24
and R25 a 180K metal film resis-
tor (brown, grey, black, orange).
 Larger hysteresis
If you prefer a larger hysteresis
(between 1 and 10°C or 2 and 20°
F, for instance for water heaters
and such-like), then fit a wire link
for R24 an R25.
20. Choosing hysteresis

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B. DISPLAY MODULE ‘P2649D’
 J (4x)
Choose temperature display :
 JC for °C
 JF for °F
1. Jumpers
 R2 : 91K (9 - 1 - 0 - 2)
2. Metal film resistor
R...
 R5 : 100K (1 - 0 - 4 - B)
 R9 : 1K8 (1 - 8 - 2 - B)
 R11 : 120K (1 - 2 - 4 - B)
 R12 : 18K (1 - 8 - 3 - B)
 R19 : 4M7 (4 - 7 - 5 - B)
 R30 : 47K (4 - 7 - 3 - B)
 R31 : 10K (1 - 0 - 3 - B)
 R33 : 22K (2 - 2 - 3 - B)
Mount for R10 :
 390 (3-9-1-B) for °C.
OR
 330 (3-3-1-B) for °F.
3. Resistors
R...
Mount for R13 :
 1M (1-0-5-B) for °C.
OR
 150K (1-5-4-B) for °F.
 For degrees Celsius, the follow-
ing resistors must be fitted too :
 R7 : 100K (1 - 0 - 4 - B)
 R8 : 100K (1 - 0 - 4 - B)
 R14 : 150K (1 - 5 - 4 - B)
 IC1 : 40P
4. IC socket, Watch the
position of the notch !
Construction

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 C4 : 100nF (104)
 C6 : 100pF (101)
5. Ceramic capacitors.
Construction
 RV1 : 4K7
 RV2 : 100
 RV3 : 10K
7. Horizontal trimmers
R...
 First look for pin 1 : if a colon is displayed when connecting the
battery, then you have the display correctly mounted. If only one
point is displayed, then you have to turn the display, fig. 1.0.
8. LCD display
25 16
34
39
40
38
37
36
35
29
30
27
28
26
7
2
1
5
4
3
6
12
9
8
11
10
14
13
15
22
24
23
21 19
18
17
20
31
32
33
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
36
27
22
21
25
24
23
26
32
29
28
31
30
34
33
35
39
37
38
40
Fig.1.0
 T2 : BC557B
Attention : For °F
this transistor should
not be fitted!
6. Transistor.

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 Pay attention to the position : the upper surface must be at 8mm
(0,3 inch) above the pcb surface (see drawing 2.0).
You may put some pieces of paper between the LCD and the pcb, to
help you holding the display on the right height.
 First solder only the pins at the four corners.
 Verify the height, and correct if necessary.
 Then solder the remaining pins.
Be very careful, for this part is not cheap!
Construction
LCD
Fig. 2.0
 C5 : 10nF / 250V
 C7 : 100nF / 250V
 C8 : 220nF / 100V
 C9 : 470nF / 63V
9. Capacitors
 LD1: 5mm Red
10. LED. Watch the polarity !
LD1
CATHODE

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 S1 : S500
11. Push button.
 IC1 : ICL7106
12. IC. Watch the position of
the notch!
Construction
Insert the plastic spindle in trimmer
RV1 as displayed.
13. Axe.

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Sensor
Calibration is performed by alternately adjusting the meter at the freezing respectively boiling-point of water.
Therefore the sensor first has to be prepared.
DON'T shorten the connection wires of the sensor, unless you are not going to fit it directly onto the pcb in
the future.
 Solder two isolated wires (75 cm or 30“) to the sensor (see fig. 3.0)
Make use of a cable of the desired length (max 10m, and preferably screened to avoid interferences) if you
are not going to fit the sensor onto the pcb in the future.
14. Sensor
Fig. 3.0

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Make the connections waterproof with heat-shrinkable tubing :
 Cut off a piece of shrinking tube with a lenght equal to 5cm.
 Slide the shrinking tube over the wires and over the sensor (Fig. 4.0).
 Heat the shrinking tube using a hair dryer or, better still, using a paint stripper.
 Take care that everything is well covered.
Connect the whole to the place marked with 'R32 SENSOR'. The connection order is unimportant, unless
with screened cable: the screen then comes on the side marked with 'SENSOR'. Connect a mains cable to
the screw connector J1-MAINS.
Sensor
Fig. 4.0

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 Attention : The connecting order (whit regard to the pcb-edge) must be the same as on the power supply
module (see fig. 5.0).
15. Flat cable
!
P2649D
P2649V
Flat cable
Fig. 5.0

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Adjustment
During assembly you already made your choice for degrees Celsius or degrees Fahrenheit version.
The adjusting method is the same for both, only the values on the display are different. The figures for
Fahrenheit are mentioned within brackets.
The first adjustment is done at the freezing-point.
 Fill a beaker with ice cubes and plunge the sensor into the melting-water (Fig. 6.0). As long as not all the ice
is molten, the temperature of the melting-water is kept at 0°C (32°F), and after a few minutes the sensor will
be at 0°C too.
 Then adjust with RV2 until the display reads 00.0 (32°F).
 After zero-adjustment, the sensitivity of the meter has to be adjusted.
 Plunge the sensor into boiling water, but see to it that the sensor does not come too close to the bottom or
wall of the kettle.
 After a few minutes, the sensor temperature has risen to 100°C (212°F).
 Then adjust with RV3 until the display reads 100.0 (212°F).
 Now let it cool down for about half an hour, and do the complete adjustment over again once more.
 Remark : when the sensor has to be replaced for any reason, then you have to readjust completely!
16. Adjustment
Fig. 6.0

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The set temperature is displayed when you push the button S1.
You can change it by gradually turning potentiometer RV1 until the display shows the desired temperature.
With the standard values for R2 and R33 (91K resp. 22K), the adjusting range is about 5 to 30°C (40 to 85°F).
You can change this range by using other values for R2 and R33 :
 You can also experiment yourself in order to obtain an optimum adjusting range for your application.
 Solder a 1M trimmer parallel to both R2 and R33 (see fig. 7.0).
 Adjust both trimmers so that you obtain the optimum range.
 Afterwards replace the trimmers by normal resistors which approximate the set value as close as possible.
17. Use
Range R2 R3
-50°C (-60°F) to 0°C (32°F) 51K 7K5
+50°C (120°F) to 100°C (212°F) 33K 12K
+100°C (212°F) to 150°C (300°F) 33K 16K
Use

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You can lower the set temperature by a number of degrees (preset with RV5), e.g. by night or during your
absence, by connecting a switch or a relay contact (e.g. a timer such like K2603 or K1682) at the place
marked with 'E.S.' (Economy Switch).
The hysteresis is the difference between the temperatures at which the output is switched on resp. switched
off. Depending on the application, a smaller or larger hysteresis may be desired: to regulate the room tem-
perature for instance, a small hysteresis is desirable. On the contrary, this makes no sense with water-
heaters, so, in this case, you should select a larger hysteresis.
You can adjust the hysteresis with RV4.
The adjusting range is about 0,2 to 2°C (0,4 to 4°F) when R24 and R25 are 180K resistors, and 1 to 10°C
(2 to 18°F) when you fitted wire links.
FIG. 7.0
Use

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The setting of the hysteresis does not depend on the set temperature. Do not set the minimum hysteresis
right from the beginning: in this case the regulation is most precise, however it could happen that the heating
gets switched on and off much too fast and too often (e.g. when the thermostat is located near the radiator).
This is not too healthy for the heating installation and/or relay, and too much energy is consumed. Therefore
start with RV4 in the middle position, and then search the ideal position for your application.
Suppressing inductive loads :
Should the operation of the thermostat get disturbed by the switching of inductive loads (even if the switched
power is not so high), then this is due to the sparks produced in the relay. In most cases this can be reme-
died by putting a VDR (e.g. VDR300) over the contacts. Moreover a series connection of a 100 ohm resistor
with a 47 or 100nF/400V capacitor can be placed in parallel with the VDR in order to further reduce the
sparks (see Fig. 8.0).
100 ohm / 0,5W
100nF/400V
VDR
(VDR300) MAINS
LOAD
FIG. 8.0
Use

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Mounting
* Spacers & screws are not included.
18. Mounting
FIG. 9.0
SENSOR
FLAT CABLE