þ Wide measuring and regulating range: -50 to +150°C (-60 to +300°).
þ Adjustable hysteresis: 0,2°C (0,4°F) to 10°C (18°F).
þ Resolution of the display: 0,1°C or 1°F.
þ Can be set for degrees Celsius or Fahrenheit.
þ Connecting capability for economy switch.
K2649
Specifications :
• Power supply and transformer included.
• Mains voltage: 220/240V (110 for USA and Canada).
• Relay output: 240V, 3A max.
• Dimensions: 123.5x62x65 mm.
ILLUSTRATED ASSEMBLY MANUAL H2649IP-1
2
VELLEMAN Components NV
Legen Heirweg 33
9890 Gavere
Belgium Europe
www.velleman.be
www.velleman-kit.com
0.000
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 (2540W) with a small tip.
•Wipe it often on a wet sponge or cloth, to keep it clean; then apply solder to the
tip, to give it a wet look. This is called ‘thinning’ and will protect the tip, and enables you to make good connections. When solder rolls off 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.
3
Assembly hints
1.3 Soldering Hints :
Mount the component against the PCB surface and carefully solder the
leads
Make sure the solder joints are cone-shaped and shiny
Trim excess leads as close as possible to the solder joint
AXIAL COMPONENTS ARE TAPED IN THE CORRECT
MOUNTING SEQUENCE !
REMOVE THEM FROM THE TAPE
ONE AT A TIME !
4
5%
4K7= ( 4 - 7 - 2 - B )
1%
4K7= ( 4 - 7 - 0 - 1 - 1 )
COLOR= 2… 5
C O D
E
KODE
COLOR= 2...5
KLEUR
CODIFI-
CATION
DES COU-
CODE
COLOUR
FARB
KODE
KODE
FARGE-
KODE
FARVE-
FÄRG
SCHEMA
VÄRI
KOODI
ORES
CODIGO
DE COL-
LEURS
I P E SF S DK N D GB F NL
CODIGO
DE CORES
CODICE
COLORE
C O D E
0 Nero Preto Negro Musta Svart Sort Sort Schwarz Black Noir Zwart 0
9 Bianco Branco Blanco Valkoinen Vit Hvid Hvidt Weiss White Blanc Wit 9
A Argento Prateado Plata Hopea Silver Sølv Sølv Silber Silver Argent Zilver A
B Oro Dourado Oro Kulta Guld Guld Guldl Gold Gold Or Goud B
Construction
R...
R...
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.
Assembling instructions :
The whole consist out of two parts : the regulating and
power supply module P2649V and the display module
P2649D
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 resistor (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.
Attention : For degrees
Fahrenheit this transistor
should not be fitted!
12
9. LED
Watch the polarity !
LD1
CATHODE
q LD1: 5mm Red
10. Pushbutton
q S1 : S500
Construction
11. Flat cable
P2649D
!
P2649V
Attention : The connecting order (whit regard to the pcb-
edge) must be the same as on the power supply module
(see fig. 2.0).
FIG. 2.0
12. IC, watch the position of the notch!
q IC1 : ICL7106
13
Sensor
13. 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.
G DON'T shorten the connection wires of the sensor,
unless you are not going to fit it directly onto the pcb in the
future.
q 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.
Make the connections waterproof with heat-shrinkable
tubing :
q Cut off a piece of shrinking tube with a lenght equal to
5cm.
q Slide the shrinking tube over the wires and over the
sensor (Fig. 4.0).
FIG. 3.0
14
Sensor
q Heat the shrinking tube using a hair dryer or , better
still, using a paint stripper.
FIG. 4.0
G 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.
15
Adjustment
14. 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. 5.0). 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.
Fig. 5.0
— 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.
G Remark : when the sensor has to be replaced for any
reason, then you have to readjust completely!
16
Use
15. Use
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 :
-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
Range R2 R3
G 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.
6.0).
— 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
R2
R33
1M
1M
FIG. 6.0
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 temperature 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.
18
Use
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 remedied 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. 7.0).
LOAD
100 ohm / 0,5W
VDR
(VDR300)
100nF/400V
MAINS
FIG. 7.0
19
Mounting
16. Mounting
* Spacers & screws are not included.
FIG. 8.0
FLAT CABLE
SENSOR
The rectangular opening in the power supply module is
used as a passage for the wiring to the mains input, the
relay output and the E.S. (Economy Switch), see fig. 9.0
Mains
Economy switch
FIG. 9.0
Relay output
20
Mounting
The display module can be mounted above the power
supply module using spacers (See fig. 10).
FIG. 10
This thermostat exactly fits into the box type B2649.
In case you use this box, you can fit the sensor onto the
pcb in such a way that it passes through the opening in the
side of the bottom. In this way, the sensor reacts more
quickly and accurately upon the room temperature, and it
doesn't get influenced by the heat-dissipation of the transformer and such-like.
21
Mounting
In case of panel-mounting, you may use a some what
longer flat cable, so you can simply mount the pcb's with
their solder sides towards each other, and the connections are easily accessible.
You also could use screw connectors for the sensor
connection. Wherever and for whatever application the
thermostat may be used, always take into account that
the mounting of the sensor determines the quality of the
regulation: the quicker it reacts upon the changing temperature, the better.
In case of liquids, this is not such a problem: you can
attach the sensor on the outside of the metal pipe or boiler
(you could use a little bit of heat-conducting paste), or make
the sensor waterproof and plunge it into the liquid.
Air however is a much worse heat-conductor, so that the
body of the sensor does not heat up/cool down that
quickly. This can be improved by circulating the air
around the sensor.
Especially in large rooms, which are heated by means of
hot air, it can be interesting to place the sensor in the
(cold) air circulation, for instance nearby the air inlet of
the convector.
The intake air (which has the actual room temperature)
then makes the sensor warm up quickly as the room temperature increases.