Common caps for two escs?

[golfito]

Then for the simple opto I eliminate that resistance in parallel and I only leave connected the series resistance between pin 1 of the opto and the signal cable that goes to the RX.

[CraigP]

The resistance across pins 1 and 2 are to discharge the capacitance of the light emitting diode. Each diode needs its own discharge resistor. I guess I’m not following what “simple opto” means.

[golfito]

Sorry. Simple Opto I call it a single 4N35. And I tried to use one of these for each channel of the futaba rx.
In that modification
How would the resistor circuit for a single 4N35 be?
Resistance 1-2 is maintained.
So, I withdraw the series resistance between pin 1 and the signal cable ?.

[golfito]

I will put a resistance in parallel, both resistances of 249ohms. It will have half of its value in both and a resulting resistance of 249ohms.

[CraigP]

Sorry. Simple Opto I call it a single 4N35. And I tried to use one of these for each channel of the futaba rx.
In that modification
How would the resistor circuit for a single 4N35 be?
Resistance 1-2 is maintained.
So, I withdraw the series resistance between pin 1 and the signal cable ?.
[ATTACH=CONFIG]156383[/ATTACH]

A dual opto is exactly the same as a single, only there’s two channels inside the device. Each channel must be wired the same. Treat each input diode the same. You can also wire it any way you want, this is just my circuit design.

[golfito]

My bad English is a limitation, excuse me.
I understand what dual opto and simple. I just wanted to have two simple opto circuits separately. And then use those two circuits to connect one in each ESC. In a RX of futaba with the dual function esc. Using the 2ch and the 4ch for the esc. Each with its opto circuit.

With the parallel, it reduced the resistance values by half. But just try it one at a time. And with the flysky rx.
*!** The real test will be with both teams together in the RX futaba. In dual mode esc. I hope not to damage any of the electronics by connecting both circuits and both ESCs.

[CraigP]

My bad English is a limitation, excuse me.
I understand what dual opto and simple. I just wanted to have two simple opto circuits separately. And then use those two circuits to connect one in each ESC. In a RX of futaba with the dual function esc. Using the 2ch and the 4ch for the esc. Each with its opto circuit.

With the parallel, it reduced the resistance values by half. But just try it one at a time. And with the flysky rx.
*!** The real test will be with both teams together in the RX futaba. In dual mode esc. I hope not to damage any of the electronics by connecting both circuits and both ESCs.

Are you having a problem when you test? It looks like it’s working in the video. I’m confused what the problem is...

[golfito]

It works. Both channels.
Only that it modifies the original circuit and the values of the resistances. To use it in the RX with "dual esc". But I have no confidence that he is correct with what he modifies. I can not prove it.


I'm going to build another opto board as its specifications and I will not use the dual esc function.
Very grateful for your help.

[CraigP]

Not sure why you’re reducing the resistance so much. This could cause a loading issue on the Rec. The Ohm Meter is lying to you. The circuit in operation does not “see” the combined resistance of 498 ohms. The led inside the device will only drop about 1.5 volts, so the parallel 249 Ohm resistor sees 1.5V across it. If your feeding 5V in from the Rec, then the series resistor “sees” 3.5V. So the Rec signal out has to deliver 20mA, well within its range. If you use your added up value of 498 ohms, which is wrong, the circuit would only pull 10mA from the Rec. So it actually pulls twice the current you think it’s using.

Not trying to be a problem, but I designed that circuit, then tested it on an electrical simulation program I use for my work. I then measured it on my DSO and posted pictures of that. The circuit is right! I’m open to debate about it if you can show me specific voltage/current information that is contrary to my stated facts. I think your just making a bunch of work for yourself and if you put that Rec into current limiting, you’ll be making more problems for your boat than the opto solves.

If I’m misunderstanding you because of the language barrier than I apologize. But you are showing half the resistance in the schematic you posted, I know that’s not the right way to go. You might want to try that with a Rec you don’t care about. Some the rec don’t have current limited outputs, so you could fry it. All in the name of science, I’ve blown piles of electronic parts up over the years!

[golfito]

I apologize for wasting your time. You have all the reason.
I used the concepts erroneously and realized that I must re-read the principles of the law of ohm. And read the data sheet. I wanted to have the circuit for a single 4n35 / ESC. Then use two of them for the dual esc. But I did not know how to solve it. It worked pure luck.

I'm going to buy the components again and build the circuit as specified. I saw the oscilloscope graphics. You did an awesome job.

I can erase the previous messages with my confusion if you want.
Thanks for the support.
Hernan

[CraigP]

I went back this AM and re-read your posts and they are misleading because those circuits won’t work like the scope shots I posted. I’m not asking to remove anything, because that’s not my place. I think you have to decide what’s best for the thread, and the many people that may read it. It seems we want to leave a path that is easy to follow. I would like to see other modelers build their own. So it would be nice to have a clean direction. Perhaps when you are done investigating I can drop in some clean schematics. There is interest in the single opto board, for single motor boats to break the ESC/Rec ground loop. There is also interest in a dual opto board, one with a single input connector driving both ESC opto’s. This mimics a Y Cable, only with isolation. The Opto Board is the “Y”. And lastly, a two input Opto Board where each input connector feeds one of the isolators, to be used for Trans/Rec packages that have Channel Mixing in the Transmitter or to come off an external mixing board, such as you found. That is my goal...

[srislash]

Craig, Mtroniks kindly cancelled my order so I’m not on the hook for 10 of those.

So I have a question, I have a couple of Spektrum RX’s (MR3000, dual outputs) that at some point along the way seemed to have one of the ESC outputs die. I’m trying to remember which setup they were in, lower voltage so ESC’s with BEC is coming to mind. Would the cause likely be that ground loop?
There were a number of issues when I started twins so I like you have a box of burnt stuff, lol ��

[CraigP]

Craig, Mtroniks kindly cancelled my order so I’m not on the hook for 10 of those.

So I have a question, I have a couple of Spektrum RX’s (MR3000, dual outputs) that at some point along the way seemed to have one of the ESC outputs die. I’m trying to remember which setup they were in, lower voltage so ESC’s with BEC is coming to mind. Would the cause likely be that ground loop?
There were a number of issues when I started twins so I like you have a box of burnt stuff, lol ��

Oh gee Shawn, thanks, LOL! Just what my wife wants to see! Kidding aside, yes, this ground loop can cause that failure. I can't believe it's taken me so long to see this... I did a poor job when I first laid out the electrical stuff in the first boat. Normally, I would spy that out from a mile away! I would love to see ALL ESC's come with Opto-Couplers, since I'm realizing (and the simulator is verifying) that a good ground can't be established at both, the Rec and the ESC. It has to be the Rec only. God only knows how bad the noise is in a twin, where the loops quadruple in magnitude. It's amazing that this stuff lives at all! It's only when I started the design process over again for my future twin build that I caught on to it...

I know many will say "it's good enough" and not pay attention. But at some point, the noise will give them some weirdness, and perhaps they spend time and effort redoing wires and placing things in others spots, never really solving the root problem.

[golfito]

Yes, excellent Craig.
I am interested in the three types of opto plates that I described.
Later I will start the construction of the circuit that you verified (simulates cable Y) As you do on the test plate (protoboard).
Greetings.

[srislash]

Oh gee Shawn, thanks, LOL! Just what my wife wants to see! Kidding aside, yes, this ground loop can cause that failure. I can't believe it's taken me so long to see this... I did a poor job when I first laid out the electrical stuff in the first boat. Normally, I would spy that out from a mile away! I would love to see ALL ESC's come with Opto-Couplers, since I'm realizing (and the simulator is verifying) that a good ground can't be established at both, the Rec and the ESC. It has to be the Rec only. God only knows how bad the noise is in a twin, where the loops quadruple in magnitude. It's amazing that this stuff lives at all! It's only when I started the design process over again for my future twin build that I caught on to it...

I know many will say "it's good enough" and not pay attention. But at some point, the noise will give them some weirdness, and perhaps they spend time and effort redoing wires and placing things in others spots, never really solving the root problem.

First off I feel for the wife, well I understand anyway.

Yes now we need to really prove this. There have been many unexplained issues over the last few years. Spektrum radios being blamed perhaps when it was something like this. Each ESC could be more sensitive than the next. As you said perhaps a over current shutdown in the rx(Rec).
Many (ok maybe just a few) have had the boat go out round a course and have a shutdown. Just over and over again. The fix?? A new Futaba radio as I recall. So someone should find out if Spektrum does undead have a Rx shutdown built in. I myself have never had an issue with Spektrum other than antenna things. So I always wondered what was up with these others. Perhaps this is it!!!