Customer:
I’ve discovered new insights into how the step-up converter behaves and I think I’ve solved the problem.
To recap the previous setup: I would enable the first step-up converter via relay R1 to step up to 5V for electronics, which worked fine. After 5 seconds, I would enable the second step-up via relay R2 to step up to 10V for an electromagnetic valve. When the valve started opening, the first step-up would go unstable, jumping to 10V or higher unpredictably. Disabling the second step-up would return its voltage to 5V. Later I found that simply disconnecting the valve—not the second step-up—was enough to bring the voltage back to 5V.
This gave me an idea: enable both step-up converters simultaneously, and only power the electromagnetic valve after 5 seconds. And it works.
I’m not certain my conclusion is correct, but it seems that if an inductive load is connected at the moment a step-up converter is switched on, it causes instability. If I connect an inductive load to an already-enabled step-up, there’s no problem. That first moment appears to be critical. I’ll be testing this setup for a while, but this seems to be the issue. I should mention that in this latest test, the battery was charged via a charger.
It’s hard to know exactly what delay is needed between enabling the step-up and powering the inductive load—perhaps just a few milliseconds—but clearly some delay is necessary. In my case it’s 5 seconds for the water fountain functionality, but I believe it would work with a shorter delay too. I suspect it has to do with the inductor inside the step-up converter and the inductor in the inductive load: while the output voltage from the converter is stabilizing, any inductive load could cause problems.
I also have a question about the Dambu board. I tried connecting an LCD via I2C but got a compilation error. I didn’t have time to troubleshoot, but it might be an Arduino IDE configuration issue. Or perhaps the Dambu processor doesn’t support that library function—specifically eRadionicaLiquidCrystal. Do you have any information about this? I’ll experiment with it once I finish the water fountain. I really like the Dambu, and I’d love to have roughly the same functionality as the Basic2. If you know any specific limitations of the Dambu, please let me know—I don’t mean memory and speed, but rather code that works on Basic2 but won’t work on Dambu.
Original message (Croatian)
[name removed] bok!
Došao sam do novih spoznaja u ponašanju step-up konvertera i mislim da sam riješio problem. J Dakle, samo da podsjetim kako je do sada sve bilo spojeno kada je bilo problema.
Preko releja R1 bi uključio 1. step-up koji diže na 5V radi elektronike i u tom trenutku je sve ok. Nakon 5s preko releja R2 uključujem 2. step-up koji diže na 10V radi el. mag. ventila i koji odmah počinje otvarati ventil i u tom trenutku bi 1. step-up podivljao. I on bi otišao na 10V ili više, kako kada. Isključivanjem 2. step-up konvertera napon bi mu se vratio na 5V. Kasnije sam ustanovio da je dovoljno isključiti ventil a ne 2. step-up kako bi napon pao na 5V.
To mi je dalo ideju da oba step-up konvertera uključim istovremeno, a samo el. mag. ventil nakon 5s. I gle čuda, radi.
Ne znam je li moj zaključak ispravan, ali čini mi se da ako je u trenutku uključenja step-up konvertera na njega priključeno induktivno trošilo, da stvar podivlja. Ako induktivno trošilo uključim na već uključeni step-up, nema problema. Izgleda da taj prvi trenutak igra neku ulogu. Sad ću neko vrijeme testirati ovakav setup, ali čini mi se da bi tom moglo biti to. Trebam napomenuti da je u ovom zadnjem testiranju baterija išla preko punjača.
Teško je sad znati kolika mora biti pauza između uključenja step-up konvertera i induktivnog trošila, možda svega par ms, ali očito neka mora biti. Kod mene je 5s radi funkcionalnosti vodokotlića, ali vjerujem da bi i s kraćom pauzom radilo. Možda ima veze s onom zavojnicom u samom step-up konverteru i induktivnog trošila koji je isto zavojnica, pa dok se napon na izlazu konvertera ne stabilizira, svaka zavojnica kao trošilo bi mogla raditi problem.
I pitanje vezano uz Dambu. Probao sam LCD spojiti s Dambom preko I2C ali već u kompajliranju je javio grešku. Nisam se stigao poigrati s tim, možda je problem u postavkama Arduino okoline. Ili Dambin procesor ne podržava tu biblioteku funkcija, konkretno eRadionicaLiquidCrystal. Imaš li kakvih saznanja o tome? Kada riješim vodokotlić poigrat ću se s tim. Damba mi se strašno dopala, pa bi volio imati približnu funkcionalnost kao Basic2. Ako znaš neka konkretna ograničenja Dambe, javi. Ne mislim na memoriju i brzinu, već baš na program koji bi na Basic2 radio a na Dambi ne bi.
Originally submitted via email support on 9 June 2018. Migrated to the forum for community visibility.