Jwells wrote:
>Ted yes you could do it that way I realize you are not asking for a change
>to the design just a clarification of how its either done or can be done
>and my information is just that sharing possible configurations.
What I was trying to do was point out that moving the PIC to the SSR board would not cause more exension cords to be needed and at the same time it would greatly reduce the amount of Cat 5 cable needed. As you said I was not asking anyone to change their design however I was trying to point out that it would be a much better design (in my opinion at least) to have the PIC on the SSR board.
> To maximize the PIC since its one of the more expensive components
>and capable of driving 8 ssr's channels and the current design most
>widely used is the 4 port ssr boards. This would waste 4 ports. New
>boards could be made to handle the PIC and 8 SSR's.
There is no reason to waste 4 ports. You could simply locate one of the 4 port SSR boards near the board with the PIC and use a short length of Cat5 to connect the 2. Or you could put the PIC on a small piece of protoboard and locate it between 2 of the 4 port SSR boards. I don't get the reason for 4 port board though. That is not very many channels. It seems to me that having 8 channels would be more efficient. Obviously it would depend on the design of a given display.
>Just curious are you planning this type of setup for 2007 yourself ?
I still haven't decided what I will ultimately do. I'd like to build something myself but I'm not entirely happy with any of the designs out there. I do want to play around with some PIC programming. On the other hand it would be easier to buy kits and put them together. I was going to do that for '06 but my budget did not allow for it.
>The current Coop buy that ends Tue. Jan. 02 2007 at 11:59 PM for the
>64 port boards that do not have the dimming capability cost 13.00 each
Thanks for the update. I don't mean this to sound snobby but I'm not interested in the non-dimming design. I do not in any way look down at the DIYers who are going this route. I consider all of them to be ahead of me because I have not built anything yet! It is simply that if I am going to goto the trouble to build something then dimming is one of the things I want it to do.
pshort wrote:
>Hopefully this doesn't end up as a near-duplicate post.
Actually I think this post that I am making is more likely the duplicate!
>PICs are not terribly expensive. The latest mouser price is $1.31 each in
>quantity of 25. So putting a PIC on each SSR board and wasting 1/2 of its
>capacity costs you an extra $.65/SSR. Add an RS485 transceiver (75176)
>and a few resistors and a zener, the 'extra' cost of putting the PIC on the
>SSR is about $1.60/SSR total. The connector costs would be the same, I
>think, but the PIC-on-SSR approach uses a lot less cable. So you have to
>compare the additional silicon expense with the decreased cable expense,
>which would vary quite a bit from setup to setup.
That is a really good point that I didn't even think of! Combine this with the idea (I mentioned above) of simply locating another 4 SSR board nearby which would be controlled by the same PIC and the cost is reduced even further.
TED
Last edited on Tuesday January 2nd, 2007 07:53 am by TED
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