Do-it-yourself automation of home heating control. Part 1



    Master Kit BM8036 and NM8036 multifunction devices can be used as the central part of a heating, cooling, ventilation, etc. control system. On the basis of NM8036, one of our customers decided to make home heating control automation and described in detail the process of implementing his idea:

    “In the article, Home Heating Automation, I wrote about what automation is needed for a heating system with a water heat accumulator (BTA). Based on the desired algorithm and the features of the heating system of this kind, I came to the conclusion that we need a programmable control unit that performs not only the functions of a thermostat, but also a timer with a calendar.

    In principle, you can just take an old computer, some Pentium 2nd, write a program for it that will perform all the desired functions - and that’s the end of the matter. I admit, I still have not lost such a mood. However, I suddenly remembered such a company where you can buy a lot of different sets for a wide variety of tasks. This is Master Kit.

    But I must say that this company supplies various kits for the assembly of electronic devices. What is a kit? This is usually a printed circuit board and a set of parts for assembly. True, there are already assembled, ready-made appliances. Actually, I used to use this service before, collected something ... And now, quite a bit rummaging in its catalog, I found a device that, on the whole, fully meets my requirements. This is a 4-channel thermostat timerNM8036 .



    There is also an analogue of such a thermostat in the catalog, but for 8 channels: BM8036 .


    * the device is delivered in a welded form with installed power keys complete with a case and 8 temperature sensors

    If you get to know more about this and the other option, then my personal choice is: 4-channel. Why? It is easy to expand to 12 channels. More precisely, both devices can be converted into a 12-channel version. That is, install 12 devices under his control. And this is not my invention, on the site of Master Kit, all this is said. My choice fell on the NM8036, as it is cheaper. However, the use of one or another option depends on the tasks, the ability to solder, etc. (it will be easier and more convenient for someone to use the finished device).

    What kind of devices can this be? Well, for example, heating system solenoids, circulation pumps, electric heaters, fans, electrically controlled valves ... Eka blew me away. Gate valves, fans ... Duc, I’m already wondering that this thermostat will not only control the heating system, but also maintain the optimal storage temperature for vegetables in the basement.

    It is not superfluous to note at the same time that you can connect just a huge number of temperature sensors to the inputs of this device. Digital sensors with high accuracy. And for gourmets from electronics, it is still possible to connect a couple more analog sensors to the ADC inputs.

    But the highlight of this unit is not even that. Its software core allows you to program work without knowing any programming languages. Everything is at the level of human understanding in Russian. Although, of course, it would be difficult for a person far from such things to cope with this. At least not immediately, not with a raid.

    But what I especially liked was the fact that this device can be connected to a computer and cast out over it no longer using its regular buttons, but from the computer keyboard. View the program, change it, upload new versions of firmware ... Is it difficult, Master? I don’t know, I don’t think so. Today is a century such that 12-year-old grandchildren, without looking at the buttons on the keyboard, beat. Well am I, dumber than them, or what? Pipes, they won’t catch us!

    Well, in short, I collected this device, debugged it. Now there’s a little thing left: put the temperature sensors in their places and create a program according to the algorithm that I need for the system to work. And this is not a pipe business. Look, Master, read how many people already use this thermostat. I didn’t make any discovery here, I just found what I need and at an affordable price.

    Well, what is required for the complete assembly of my control unit? So I figured it out on my Wishlist-winders and decided to use all 12 channels at once. Maybe not right away, but the control unit needs to be assembled complete. Therefore:

    1. Timer-thermostat NM8036 1 pc
    2. Executive relay block NM4411 3 pcs
    3. Power supply PW1220D1 pc
    4. Digital temperature sensor DS1822 4 pc

    That's all I bought in the online store. Temperature sensors, in fact, come with a timer, there are already 4 of them. But I still took the extension 4. They will not be superfluous. And in the local store I looked at the case for the control unit, where you can stick all these components.

    Master Kit himself does not engage in trade; various dealers-shops, including online stores, do this. There are no supermarkets in my village, so I use online stores.

    Here is the build process



    Now let's talk about the assembly and launch of the heating control unit based on the NM8036.



    Master Kit has a very good set of instructions. There is a link to the kit description page at the end .

    But today I didn’t start the story in order to repeat this instruction. There are various underwater pebbles and cobblestones that are not mentioned in the instructions, but in my practice I either came across, or miraculously avoided one, but I could stumble. This is what I’m talking about.

    I will not tell and show how to solder elements to a printed circuit board. Of course, this is not done with a blowtorch, and a certain minimum skill, of course, is highly desirable. Here the rules are simple: accuracy and attentiveness, conclusions and contact pads try not to overheat.

    Schemes with sets are available, lists of elements are enclosed, names on the elements are written - have, as they say, eyes and hands. But I want to remind you of one thing: after assembly, cleaning and washing, do not rush to turn it on immediately. Take it, Master, a larger magnifier and carefully check each soldering. EVERYONE! So that the circle was smooth, so that the closing nozzles of solder did not stretch from it to other contacts. The lion's share of malfunctions arises precisely from poor-quality soldering.

    Insert the processor (controller) into the socket correctly. This is the largest microcircuit, it has a recess at the end, indicating the beginning of the conclusions. The wiring diagram shows where this recess should look.

    Collected? Checked? Now check again. Test shot before launch. Shot? Well, cross yourself on the image and poke the power connector. Just keep in mind that if you put it in the wrong direction, the pleasure will be doubtful, and the result is not the same.

    Look, there are two smaller connectors near the COM connector - right and left. The one on the right is a connector for connecting sensors. And the power connector is the one to the left of COM. So, the power connector pokes very well in the sensor connector. Be careful, otherwise you run the risk of running into trouble.



    COM connector For what? To connect to a computer ... and more. The controller outputs for controlling the loads OUT0, OUT1, OUT2 and OUT3 are connected to the contacts of the same connector (see XS1 connector in the diagram). That is, these 4 outputs can be used directly from this connector.

    Not bad, of course, but if you do not use them here, and use the connector only for connecting to a computer, then do not try to use any cable for connection. In this cable, wires to the contacts of the outputs can also be soldered. It is not known how this may end. The instructions say how to unsolder the cable to connect to the computer - do it.

    Further. These blue little terminal strips (XS6 - XS9) that to the left of the connectors may not be installed at all if you intend to use NM4411 sets for control. Moreover, you can also not solder all the elements that are provided in these output stages. All that is on this fragment of the NM8036 circuit (there are 8 more resistors and 4 optocouplers here).



    These elements are not needed (fewer rations - a more reliable device). But how then to connect the outputs of the controller with the inputs of the NM4411? Duc, as ... directly.

    After all, I said that in this set there are only 4 outputs, to which, accordingly, only 4 loads can be connected. And software, controller firmware can provide work with 12 loads. At the same time, each of them is connected directly to the controller contacts (although, of course, the first 4 can be taken from the COM connector, standardly).

    And how directly?

    If you look at the board NM8036 from the rations, then its appearance will be approximately the same as in this figure (to enlarge click on it). The outputs of the control channels from the 1st to the 12th are numbered with the corresponding numbers. Two analog inputs (A1 and A2) are also numbered, which are also processed by the new controller firmware.



    If, Master, you watched the video of the assembly, then, of course, you noticed a wire harness soldered to the controller pins on the back of the board. Through this flagellum, I connected the indicated pins to the connector on the additional board.

    And there another harness already went, from this connector to the executive relay boards NM4411 and two switches, which were connected to the analog inputs of the controller. What are the switches for? I set them to switch the operating modes of the heating system.

    Heating control of a private house with a boiler and a thermal battery is not solved unambiguously. After all, it’s not just “turned on / off”. The operation of the boiler in the accumulation of thermal energy is already a separate mode, different from the mode of heat consumption. My first switch is on / off the “Boiler” mode, which just corresponds to the operation of the boiler.

    The second switch in my case includes heating the bath. In standby mode, the rooms of the dressing room, sink and sauna are maintained at a temperature of 16 degrees. When heating is turned on, the temperature in the sink rises to 35 degrees.

    The mode switch circuit is simple, it is a pair of 1 kΩ resistors soldered to the toggle switch. The top resistor is connected to terminal 10 of the controller (VCC, power + 5V), and the lower one to terminal 11 (GND, common).

    It remains to supplement this article with considerations for choosing a case. In my case, the choice of a plastic case turned out to be very successful, which came across in one of the local electrical goods stores. Some crowding in it was completely compensated by a rather appropriate transparent window for placing an NM8036 block with a display under it. It also housed the power supply, and 3 NM441 control cards with 4 channels each.



    The keyboard and toggle switches of the mode switches managed to be fixed on the inside of the cover. Thus, a good heating control unit for a private house turned out.



    To be continued..."

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