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W1209 thermostat, test, opinion, applications

TechEkspert 13920 54
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  • W1209 thermostat, test, opinion, applications
    The W1209 thermostat can control a heating or cooling device. The LED display shows the current temperature with a resolution of 0.1C, measured with a sensor based on the NTC element. The simple menu of the system allows, among others, to define the type of controlled device, calibrate the thermometer readings, and determine the hysteresis range. The system is supplied with 12V and consumes ~ 16mA with the relay turned off, while the relay coil is powered, the current consumption increases to 65mA. Relay contacts, as described, can switch 20A at 14VDC and 20A at 125VAC. A plexiglass housing is included with the thermostat.

    The W1209 thermostat will soon appear in the elektroda.pl gadgets.

    To set the set temperature, shortly press the microswitch marked SET (the digits on the display will start blinking) and use the + - buttons to set the temperature to be stabilized by the thermostat. We can set the value from -50C to 110C.

    Holding the SET button for longer than 5s displays the menu items from P0 to P6. Entering the settings of a certain menu level is done by pressing the SET button.

    P0 - select the type of connected device:
    H- a device generating heat, i.e. a heater, e.g. in the form of a resistor
    C- cooling device, e.g. fan or Peltier module, C is the default setting

    P1 - we set the hysteresis, i.e. the deliberate interval between switching on and switching off an element, by default they are 2C (0.1-15 adjustment),
    e.g. in case of cooling and the thermostat temperature is set to 20C, cooling will be turned on after reaching 20C,
    while cooling will be turned off at 18C (2C hysteresis). Setting the hysteresis will reduce the number of switchings of the relay, increasing the life of the contacts.

    P2 and P3 - setting the maximum and minimum temperature (by default set to the maximum and minimum measurement, I do not know what is the practical application)



    P4 - temperature sensor calibration -7C to 7C. A one-point calibration is debatable, but for the thermostat's setpoint temperature it may make sense.

    P5 - delay time of switching on the relay.

    P6 - extreme temperature alarm, when the temperature reading reaches the set alarm threshold, the relay will be turned off, the symbol --- will appear on the display. You can set this value to a temperature that is dangerous for the system, in an emergency the heater power supply will be turned off.

    The NTC sensor is closed in a metal housing which increases its resistance to damage. When the sensor is disconnected, the thermostat displays LLL. Room temperature readings are the same as with a thermocouple multimeter.
    W1209 thermostat, test, opinion, applications

    Connecting the controlled receiver is very simple. The relay is connected in series in the receiver power supply circuit. We supply 12V DC to the thermostat.
    W1209 thermostat, test, opinion, applications

    Let's make a test and use a 4.7om resistor powered from 12V as a heating element. Place the sensor so that it measures the heater temperature. At the same time, we can record the temperature of the resistor.
    W1209 thermostat, test, opinion, applications
    We set the thermostat to 45C and see how the on / off control is doing.
    W1209 thermostat, test, opinion, applications

    Considerable temperature fluctuations caused by the "inertia" of the system are visible. Around 45C you can see the moments of switching on the relay, but despite switching off the power supply to the resistor, the temperature rises for some time, then the temperature drops until the relay is switched on again. This example shows that the accuracy of the temperature sensor and measurement may not be of great importance in on / off control. Such simple control will prove itself in many applications. In more demanding applications, the heater can be controlled, for example, by PWM or phase, and even a PID controller as a controller.

    In the set with the W1209 thermostat you will find a plexiglass housing.
    W1209 thermostat, test, opinion, applications

    Where do you see the applications for the W1209 thermostat?
    W1209 thermostat, test, opinion, applications

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    TechEkspert
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  • #2
    ElectroTom
    Level 25  
    And how to measure negative temperatures, e.g. -10 degrees Celsius or - 20.
  • #3
    Niebieski
    Level 11  
    For me, the third season controls the central heating pump.
  • #4
    miszczo997
    Level 28  
    How are minus temperatures indicated? Somehow I was recently looking for an alternative to a mechanical freezer thermostat because I couldn't find a suitable one for my medel and was considering buying a stc1000 ($ 10) regulator. I rejected the W1209 right away, because after the Chinese descriptions I concluded that it can only control the heating elements. If I had known then that it can also cool, I would have used it for sure. Especially that with the old thermostat there was a lot of space and I would have put some power supply there.

    Added after 4 [minutes]:

    It is a pity that there is no buzzer, because it would work perfectly with options P2, P3 and P6. The control microcontroller is some stm8? Maybe there are some software sources.
  • #5
    TechEkspert
    Editor
    @ElectroTom @ miszczo997 negative temperatures are indicated by a minus,
    with two-digit numbers the resolution of indications is reduced:
    W1209 thermostat, test, opinion, applications W1209 thermostat, test, opinion, applications

    The control system is a Chinese nouvoton N76E003AT20 enriched 8051.

    @Blue i.e. a durable product, it starts the circulation pump when the water temperature rises and stops when it drops?
  • #6
    Granat :)
    Level 34  
    The biggest disadvantage of this thermostat in my opinion is that when the maximum temperature (I don't know how the minimum) is reached in cooling mode, the relay is turned off.
    Let's assume that the cooling does not work and the sensor reaches 110 ° C, but the relay should not turn off the actuator, i.e. cooling, because the temperature will increase even more.
  • #7
    krisRaba
    Level 31  
    Granat :) wrote:
    The biggest disadvantage of this thermostat in my opinion is that when the maximum temperature (I don't know how the minimum) is reached in cooling mode, the relay is turned off.
    Let's assume that the cooling does not work and the sensor reaches 110 ° C, but the relay should not turn off the actuator, i.e. cooling, because the temperature will increase even more.

    This may be a deliberate safeguard, i.e. the controller switches the actuator on, but sees no changes in the feedback signal. It may be a situation that you write about, e.g. cooling does not work, but there may also be a lack / damage of the sensor (although it is supposed to be missing by LLL) - then switching on the actuator (heater, compressor, air conditioner) may be an error and continuous operation can damage them if they are not adapted to it (and not all are). Overall, the description of P6 suggests intentional action. The question is, do you have to set P6 or not?
    In fact, knowing what you are controlling, i.e. whether continuous work can cause damage or not, behavior in this situation should be configurable.
    On the other hand, this is a very extreme case when you are cooling and maybe quite the case when you are outside the thermostat's operating range. I understand that you are not able to cool something down to the set 25 degrees Celsius, because due to e.g. high sun exposure, the air conditioner or other devices with poor performance swing e.g. around 40 degrees ... Then it should actually cool 100% of the time, despite not reaching the set temperature. But a complete lack of response to the operation of the thermostat and going beyond the operating range is rather a mistake.
    On the other hand, for "critical missions" something like this is unlikely to apply ;)

    Well, one more question .. because it may be the opposite (unless you state it on the basis of usage, not just the description from the first post). Ie. you set the maximum temperature in heating mode, if for some reason the regulator would like to exceed a temperature that is dangerous for the system, it turns off and, similarly for cooling, you set the minimum - you chilled too much, squeak, off ;)
  • #8
    AndyNW
    Level 11  
    Hello, I control the CO circulating pump in the furnace. OK.
  • #9
    nici
    Moderator of Car Maps
    Granat :) wrote:
    The biggest disadvantage of this thermostat in my opinion is that when the maximum temperature (I don't know how the minimum) is reached in cooling mode, the relay is turned off.
    Let's assume that the cooling does not work and the sensor reaches 110 ° C, but the relay should not turn off the actuator, i.e. cooling, because the temperature will increase even more.


    You do not need to use this feature, it can actually be troublesome in some situations.
  • #10
    TechEkspert
    Editor
    @krisRaba P6 can be set to OFF.
  • #12
    cocokoko
    Level 11  
    I have been using two such thermostats for two years. One controls the hot water circulation pump, the other controls the relay that activates the electric heater when the water temperature in the boiler drops below the set value.
  • #13
    dgproject
    Level 12  
    I use three such modules to control the airflow power in the DGP installation in the fireplace and they do well with the appropriate setting of parameters.
    The only drawback, in my opinion, is the lack of a full transmission Inka connector, which forced me to solder at the bottom of the PCB ;) W1209 thermostat, test, opinion, applications
  • #14
    vodiczka
    Level 43  
    TechEkspert wrote:
    Room temperature readings are the same as with a thermocouple multimeter.
    I read on the electrode forum that while the indications in the range of 10-30 ° C are correct with an accuracy of 1 ° C, as the temperature increases, they are burdened with more and more errors.
    When I receive the ordered copy, I will check and report the results in a wider temperature range.
  • #15
    Rezystor240
    Level 41  
    an interesting thing about this thermostat.
    For me, it would be used with a laminate etching machine.
    I can never sense the matter and sometimes I can boil acid.
    This thermostat fits perfectly, if the limit is over and it will still be in the store, I take it.
  • #16
    brofran
    Level 39  
    I believe that the range of voltage of the executive relay contacts (24 and 125 V) is a big disadvantage. After all, the typical voltage of our home installations is 240 V AC. :cry:
  • #17
    vodiczka
    Level 43  
    brofran wrote:
    After all, the typical voltage of our home installations is 240 V AC.
    It will withstand 125V, it (judging from previous posts) will also withstand 240V at a much lower current, and at 20A I do not believe it, despite the manufacturer's assurances.
  • #18
    Granat :)
    Level 34  
    P6 does not work on off, only a range is set. I have it set to max, ie 110. The sensor is on the boiler flue, at a distance from it, otherwise it would be 300 ° C. Rarely, because rarely, but if you want to, you can light it up so that the temperature rises. The thermostat controls the buffer charging pump.
    But these are only temporary, I've already figured out a better way .. and a new boiler ;)
  • #19
    AndyNW
    Level 11  
    Hello, I apply to CO in a single-family home. It works fine
  • #20
    Niebieski
    Level 11  
    TechEkspert wrote:
    @Blue, which is a durable product, starts the circulation pump when the water temperature rises and stops when it drops?


    I have a single-function boiler and a heat exchanger. The thermostat controls the pump in the radiator circuit. It turns it on when hot water from the boiler appears and turns it off when it cools down in the pipe.
  • #21
    vodiczka
    Level 43  
    TechEkspert wrote:
    P4 - temperature sensor calibration -7C to 7C. A one-point calibration is debatable, but for the thermostat's setpoint temperature it may make sense.
    How to understand? Is it so that after setting the selected temperature I can compensate the difference between the actual and the measured temperature and displayed at the time of switching the thermostat, as long as the difference between them is not greater than +/- 7 ° C.
  • #22
    TechEkspert
    Editor
    This should be understood as a single point calibration,
    the thermostat shows us 20.5C, and the exact thermometer 20C,
    we correct the indication so that the thermostat at this point shows 20C,
    as I wrote in this system, such calibration is debatable.
  • #23
    vodiczka
    Level 43  
    TechEkspert wrote:
    as I wrote in this system, such calibration is debatable.
    If we assume that it is not a sensor calibration but a compensation or correction of indications, this is a helpful solution. Unfortunately, I just received the thermostat today and it is pale. In the negative temperature range -24 ° C to -30 ° C (indications of the DT 9908A meter), the thermostat shows the temperature by approx. 10 ° C higher, i.e. the difference in indications is greater than the possible correction range.
    After introducing the maximum correction, i.e. -7 ° C, the difference decreased to three degrees, e.g. the meter showed -28 ° C and the thermostat -25 ° C

    Added after 1 [hours] 11 [minutes]:

    The thermostat is factory set to the cooling function (C), the activation temperature + 28 ° C and the hysteresis of 2 ° C. In the temperature range of + 18 ° C to + 50 ° C it is better. After introducing the -5 ° C correction, the differences in the meter and thermostat indications in the above-mentioned temperature range do not exceed 1.5 ° C
    The introduced correction is saved in the memory and does not need to be re-entered after switching it on again.
  • #24
    Freddy
    Level 43  
    @TechEkspert Correct the description a bit:
    Quote:

    P0 - type of work H-heater / C-Cooler cooling
    P1 - hysteresis (0.1 ° C ... 15 ° C, default 2 ° C).
    P2 - upper operating temperature limit from -45 to 110 ° C ... (default 110 ° C).
    P3 - lower operating temperature limit -50 ° C ... 105 ° C (-50 ° C by default) - P2 and P3 allow to narrow the temperature range for safety reasons (limits of possible activation temperature settings)
    P4 - temperature correction (-7 ° C ... + 7 ° C, the default value is 0 ° C) - Allows a simple calibration to improve the accuracy of the measurement (only characteristic shift);
    P5 - relay operation delay (0-10 s, default 0) - It is sometimes necessary to delay the refrigerator compressor;
    P6 - alarm for too high signal temperature (0 + 110 ° C, disabled by default).

  • #25
    Justyniunia
    Level 35  
    I want to build a lawn mower based on this thermostat, but ...

    # 1. How to measure the temperature of B327? Because probably not directly?
    Do you have a patent for shielding the sensor from acid, or maybe you don't have to?

    # 2. Is the use of power resistors as heating elements a good idea?
    You could use a 12V power supply and this factory 14V / 20A relay.
    In total, the temperature maintained at 40 * C does not require a heater with a power of hundreds of watts.

    PS:

    Horizontal lawn mower in the form of a cuvette (a cuvette from an old kitchen scale), rocking with a motor with a gear.
  • #26
    vodiczka
    Level 43  
    Justyniunia wrote:
    Do you have a patent for shielding the sensor from acid, or maybe you don't have to?
    I wouldn't risk without cover.
    The easiest way to apply a protective layer is to dip it in the varnish 2-3 times. Unfortunately, I will not tell you what.
    Does your thermostat require a temperature correction when measuring room temperature? If so, how big?
  • #27
    Justyniunia
    Level 35  
    At the melting point of the ice the thermostat showed 1.9 ° C, it was calibrated down by these 1.9.
    Now it shows 0 * C
    Under the tongue I have 36.5 * C, which would be correct.
    In the room, alcohol shows 24.5 dashes, thermostat 24.4 * C
    I still have to check the boiling water, but I think now everything is OK after calibration.
  • #28
    marycyś
    Level 12  
    Is it possible to change the software of this driver?
  • #29
    TechEkspert
    Editor
    Theoretically, everything can be done if the microcontroller allows for re-programming. However, in this case, you would have to write the software from scratch, as well as draw the driver diagram and use the appropriate compiler for the microcontroller.
    This version is based on the N76E003AT20 (Chinese enriched 8051), I've also seen similar copies with some ST.
  • #30
    miszczo997
    Level 28  
    For those done on stm there are modified software among others this https://github.com/TG9541/W1209
    also saw some specials for brewers.
    For the N76E003AT20 I did not find anything, probably because to program it you need quite an expensive programmer.