QUOTE (Richard Johnson @ 3 Sep 2008, 03:08)
<{POST_SNAPBACK}>***Why we made circuit design decisions is not really the sort of discussion for a forum.
Why not? If pictures are presented to a forum showing what an item looks like, surely they are just as likely to prompt questions as anything else.
After all, you wouldn't expect people to refrain from asking why Hornby etc. had chosen to do something in a particular way when presented with a picture of one of their items. That is what these forums are all about.
QUOTE However, to clarify a little for you. In fact there are 2x bridge rectifiers on the opto board, not one.
Isn't that simply because it is a dual board? Unfortunately I can't see the picture where I am at present because Photobucket is restricted here, so I am working from memory.
QUOTE The opto board is an added project we really didn't originally intend however we produced it as it was clear that there were some possible applications that might compromise reliability and that was completely unacceptabe to us, so it is made perhaps heavier than needed but it is bulletproof.
Not doubting that, but unless I have completely misunderstood the intention of the design, the rectified control signal still has to pass through the opto LED, so I can't see how that is any more bulletproof than my suggestion, which if feasible would have reduced your component count and board size (and therefore cost) by moving the rectification function into the opto itself.
QUOTE Cost isn't an issue: Our component pricing is nothing even similar to retailers such as Rapid. Durability is.
Cost is ALWAYS an issue. However, from experience I can believe that the component cost has little bearing on the eventual retail price. That is common throughout the commercial world.
QUOTE The Opto boards are now provided totally free of charge where clients specify at the time of purchase that they will DCC control the MS.
Fair enough, you are bearing the cost - which seems even more reason to adopt the simplest possible arrangement available.
Sorry if this all seems a bit critical, but my interest in such matters tends to dominate the thinking. Dealing with this sort of circuitry on a daily basis myself, as I do, automatically prompts questions no matter how hard I try not to get involved!
