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Has anybody had problems using opto-isolators?

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Old 02-13-2003, 09:21 PM
  #1
CJ2002
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Default Has anybody had problems using opto-isolators?

Guys,

I've been using opto isolators in jets and large scale aerobatic models for some years with no problems at all.

As a result of a piece I wrote in an English magazine recently, the English distributer of JR products has written to me stating, et al, that opto isolators are "NEVER necessary and are NOT recommended with JR receivers and will often lead to unexpected side effects such as continuous servo chatter".

Appreciating that there are commercial reasons for saying this, and leaving aside any opinions as to whether or not optos are necessary, I just wondered if anybody out there has experienced any problems that they could definitely attribute to the use of an opto isolator - particulary when used with JR equipment?

TIA,

Dick Spreadbury
England
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Old 02-15-2003, 05:01 AM
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Default Has anybody had problems using opto-isolators?

Sir. Do we call it something different? What does it do? Thank you.
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Old 02-15-2003, 05:48 AM
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Default Has anybody had problems using opto-isolators?

Hi Dick,

I am using the S.M. Services opto-isolator on my Boomerang without any problems. In fact, it has helped increase my radio range. No servo jitters or anything of that sort. I use a mixture of servos, from Jr, Futaba and Hitec. My radio is a JR PCM10X and the receiver I use in this airplane is a Graupner/JR SPCM nine channel, single conversion at 35 Mhz.

What is Terry's opinion at S.M.?

BRG,
Chris
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Old 02-15-2003, 05:51 PM
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Default OPTO STUFF

Howdy lads,

Hope your winter is better than ours....been a totally wet day here. Hope weather changes soon or at least moves closer to Cyprus than say here.....hehehehh!!!

I havent used the Opto yet since I am using 41mhz frequency.
Apparently this stuff has not yet been tested on this frequency and at the moment I decided not to use it. However, having said that I intent to try it out on a trainer plane and see what reactions, if any, this stuff has on that frequency. If it has already been tried and tested I would wish to have some feedback....saves me a bit of a hassle.

I will be following this thread as Dick's note is interesting.

Meanwhile, can you lend me your umbrella, Dick?

Regards


Reuben
Malta
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Old 02-15-2003, 09:33 PM
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Default Has anybody had problems using opto-isolators?

Hi Reuben,

Likewise, the weather has been lousy for three months now, can you believe this s***t? So, we both are in the same situation, it seems, we now have to move further south for some good flying weather.

BRG,
Chris
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Old 02-15-2003, 09:47 PM
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Default OPTOS AND ALL THE REST

Hi Chris,

Glad we are not the only ones!

I bet Dick has something to do with all this too? I think he is pushing the clouds our way so he will have fun with his toys!

Hi Dick, hope family is ok!

Regards

Reuben
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Old 02-15-2003, 10:39 PM
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Default Has anybody had problems using opto-isolators?

Hi Dick,
Like yourself I have used the smc opto with large petrol
models, never had any problems. When I first used one I checked
it out with a scope, the signal waveform transfers through the
opto with very little change on its way to the servo, I also set
up a noise source next to long servo leads and none got back
through the opto to the rx, thus its doing its job well, certainly
I have not suffered any problems with their use in many flights.
The only thing I will say is because you are using
two battery supplies you are doubling your fault liability, I have
gone away from the opto myself and just use toroid cores from
Multiplex on leads greater than 2ft (non active devices, non
existant component count=total reliability).
Would like to know the technical reasoning that JR
are using, the only difference I can see is that the current
load on all the channel outputs connected to the opto would be
constant, would have thought this would be a good thing???
Mike G
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Old 02-15-2003, 10:41 PM
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Default Has anybody had problems using opto-isolators?

Quote:
Originally posted by cairoman
it seems, we now have to move further south for some good flying weather.
Chris
We have just had a glorious flying day in UK. Rather cold, but blue skies and light winds.

Dick, since Futaba and JR make their range of equipment mainly for the USA market due to the high volumes, and in the USA they fly a lot of jets and large models, is there a hidden message in the fact that Futaba and JR do not themselves make opto-isolators, line drivers, ferrite rings etc? If there was a need, wouldn't Futaba and JR be making these items to get the lion's share of the sales? I begin to wonder if the "need" is just created by the third party manufacturers of opto-isolators?

Harry
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Old 02-15-2003, 11:47 PM
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Default Has anybody had problems using opto-isolators?

Mikg,
Did you do the same tests for noise/interference transfer using the toroids? If so how did they compare?
I've used SM Opto isolators for some years now with very good results. Better range, no chatter, no problems on Boomerangs and other big models after over 300 flights on both 35 and 72 Mhz.
I have doubts about toroids but always willing to learn something!
I think Dick has been advised as mentioned by those with an axe to grind!
Alan C
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Old 02-16-2003, 02:24 AM
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Default Has anybody had problems using opto-isolators?

Hi,
Did'nt perform the same checks with the cores, basically
because I have used them at work and they work well. Next
time I do a set up will do so and let you know the results.
If I get it done in time will let you know at the JMA AGM.
Mike
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Old 02-16-2003, 09:26 AM
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Default Has anybody had problems using opto-isolators?

Quote:
Originally posted by cairoman
Hi Dick,

I am using the S.M. Services opto-isolator on my Boomerang without any problems. In fact, it has helped increase my radio range. No servo jitters or anything of that sort. I use a mixture of servos, from Jr, Futaba and Hitec. My radio is a JR PCM10X and the receiver I use in this airplane is a Graupner/JR SPCM nine channel, single conversion at 35 Mhz.

What is Terry's opinion at S.M.?

BRG,
Chris
Hi Chris,

Thanks for that....I haven't spoken to Terry as I wanted to get opinions/findings from practical users first. I posted the same enquiry on the giant scale forum and have received a few interesting comments whereby some guys have experienced problems with optos (not SM) and I've had a PM from an English friend who has had problems with optos, but not of an RF nature.

One very good point that has been made is that the parts count goes up and, therefore, the likelihood of a failure increases and, because the opto can be seen as a 'belt and braces' device, maybe we're introducing a potential problem that we can avoid. That arguement holds whenever you add anything to a system, of course but the degree of likelihood of failure is also dependant on the type/quality of components you use - which is why I mentioned use of good quality toggle switches, etc, in the article. From this point of view, whether or not to do something is a matter of individual risk assessment, I suppose.

When I wrote the piece for RCMW, I was careful not to make any recommendations IRO opto use ('cos anything we want to add to our systems as an afterthought is up to us) but, as I've already said (touching wood) I've never yet had any problems using them and, on the evidence I've gathered thus far, will continue to do so.

Sorry about the poor weather that Reuben and yourself are having to put up with....although, I daily talk to aircrew who are currently transiting through Cyprus who tell me it's getting lovely and warm out there! (I guess there's no pleasing some people!!).

Keep well Chris and, you never know, if I can hitch a ride with one of our crews, I might just turn up at the salt lake for some flying!

Cheers,

Dick
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Old 02-16-2003, 03:01 PM
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Default Has anybody had problems using opto-isolators?

That'll be wonderful mate. Really looking forward to fly the MR Hunter out of RAF Akrotiri like it used to, ages ago. This will put nostalgic tears on Chris Golds' cheeks for a moment or two.

BRG,
Chris
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Old 02-16-2003, 05:37 PM
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Default OPTOS

I like this thread as its been quite informative.
On another note Chris mentioned the MR Hunter. Is the developement of this plane ready? I mean is it available in kit form already?

I believe the web site mentions Spring 2003 as a target date for completion, if not mistaken.

Regards

Reuben
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Old 02-16-2003, 06:13 PM
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Default Re: OPTOS

Quote:
Originally posted by F86_SABRE

On another note Chris mentioned the MR Hunter. Is the developement of this plane ready? I mean is it available in kit form already?

I believe the web site mentions Spring 2003 as a target date for completion, if not mistaken.

Regards

Reuben [/B]
Hi R,

Mick'll be at the JMA AGM on 8 March so will get the gen then (I hope - trouble is, you run out of confidence when several deadlines are missed!!). Need to speak to you soon re Mirc and ICQ.

Cheers,

Dick

PS...glad the weather's been crap!!!!!!!!!!!!
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Old 02-16-2003, 06:48 PM
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Default Has anybody had problems using opto-isolators?

Re: MIRC, yeah, me too!!!

I changed computer recently and lost all MIRc settings. I miss very much talking to you guys.

R, the weather has been very good today, hope it holds for a few more days...I'll go flying ASAP.

BRG,
Chris
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Old 02-16-2003, 07:15 PM
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Default opto isolator

seems like you guys across the pond use the isolators alot...

Nelson Hobbies over here sell the S.M. services unit. I have been curious as to the reliability of the unit. I would love to have the advantages the unit has to offer but I am one of those people that have a firm belief that having the least # of parts in a system is reduces the chances of failure of that system.

Does anyone know or has anyone heard of any failures of the S.M. services unit??? And those of you who have had failures with any brand of isolator....what type of failures have you experienced??? complete unit failure, partial failure, etc.??
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