Regulyator Oborotov Ventilyatora 220 Voljt

Razvojne tendence traktorskega parka v Slovenijii. The development trends. Meaning that ventilation must be under the control of the operator 6, 9. Sep 7, 2004 - N. Ageyeva, 11 pp. Characteristics of Economic Regulators Dis. Of Ventilation and Air Distribution in. RUSSIAN, bk, ıpoznaniye obratov. 220 kV and 380 kV Outdoor Switghing Sa*.

Description The prototype I made earlier wasn't working as I expected, nor wasn't looking as I expected. I wanted a device that look more professional, is smaller, etc. For power supply I simply use 7805 voltage regulator with 12V zener diode connected on input (for preventing any spikes from unstabilized power supply I used).

I need 12V for driving the coid and the fan motor. Because of very little free room in the base, I didn't use any capacitors with 7805, but I works!

As mentioned before, there are 2 PIC microcontrollers in the base. 12F683 uses it's internal 8 MHz oscillator and is programmed for making stable frequency of 25 kHz. Later I found out that L293D wasn't meant for driving loads at this frequencies.

But as i said, it works. The other PIC - 16F688 was meant for communication and fan motor PWM.

At the end it just turns on/off the L293D for driving coils and controls motor with PWM. (there is a mistake I made still present in Eagle schematics - the motor is connected between transistor's emitor gate and ground instead of being connected between 12V supply and transistor's collector gate). Picture 1, 2: base printed circuit Rotor I used a little bigger printed plate for 3 PIC microcontrontrollers, eight LEDs, DS2417 one-wire time IC, DS18B20 one-wire temperature sensor, 3V lithium battery, IR receiver and some other elements.

PIC microcontrollers are used to decode received IR signals from remote control (12F683), control LEDs in the way to display data (16F688) and to control, what should be displayed (16F876A). AC voltage induced in the coil is first rectified and stabilized using 470µF capacitor. I used simple gretz element (4-diode bridge rectifier) which is, as I later found out, to 'slow' for these higher frequency AC (after additional testing, I found out, that by using fast shottky diodes, I can get the additional 1V for power supply). To overcome the spikes of induced voltage when there is no LED on, I also used 5,1 V zener diode. Nevertheless, I could get only 3V to PIC microcontrollers, which was the source of many subsequent problems found. For instance, IR receiver/demodulator needs stable 5V and does not work if the voltage drops. Pictures 3, 4: the circuit in rotor Firmware 1.

The base 16F688 is programmed to control. Sorry, not enough time to translate this completely.

Please use google translate until then. Program v PIC-u 16F688, ki nadzoruje dogajanje v podstavku najprej vključi vzbujanje tuljave preko PIC-a 12F683. Zatem počaka 500 ms ter nato požene motor do polnih obratov. Pri polnih obratih pusti motor približno 50 obratov, nato se začne izvajati del programa, ki skrbi za stabilizacijo hitrosti vrtenja na približno 10Hz.

To sem realiziral s visokofrekvenčno PWM kontrolo motorja z natančnostjo 50 korakov. Merjenje hitrosti/časa obhoda je izvedeno v prekinitveni rutini. Zaradi pomanjkljivega načrtovanja IR fotocelice, na vhod mikrokontrolerja ne dobim digitalnega signala temveč analognega, ki ga moram ustrezno obdelati.

V prvem koraku izvedem svojo metodo računanja povprečja, ki ne potrebuje celotne tabele meritev v spominu. Prejšnjo vrednost povprečja pomnožim z n, prištejem trenutno izmerjeno vrednost ter delim z n+1. S prilagajanjem n lahko določam hitrost sledenja povprečja izmerjenim rezultatom.

V tem primeru sem izbral vrednost 3, ki je dala ravno pravo odzivnost. Po izračunu povprečja, dobljeno vrednost primerjam s fiksno vrednostjo. Zamisel je bila, da bi se program prilagajal na temno/svetlo okolje in bi gledal, kje izmerjene vrednosti odstopajo od povprečja. Zamisli žal nisem uspel realizirati zaradi raznih odbojev, napak, ki jih nisem predvidel. Vseeno da fiskna vrednost presenetljivo natančne rezultate.

Če ugotovim, da je rotor nad začetno pozicijo, shranim čas obhoda v posebno spremenljivko ter prilagim razmerje za PWM regulacijo motorja. V PIC-u 12F683 je program precej enostaven. Takoj po zagonu začne izhod preklapljat z določeno frekvenco. Oba PIC-a tečeta z notranjim oscilatorjem pri 8MHz in sta povezana preko ICSP vmesnika, kar mi omogoča, da naknadno spreminjam program, čeprav sta v vezje čipa prilotana brez podnožja (prostorska stiska). Rotor Če začnem kar z IR sprejemnikom v PIC 12F683. Namenjen je za sprejem ukazov po NEC in RC-5 protokolu. Drugi PIC 16F688 prav tako deluje z notranjim oscliatorjem pri 8 MHz.