Re: If ...
- From: Lester Caine <lester@xxxxxxxxxxx>
- Date: Fri, 08 Jun 2007 10:51:53 +0100
beamendsltd wrote:There's no cables needed - CAN is a 2-wire bus (usually has 4 inIndeed, a major drawback of proprietry standards, or ex ones. TheI think we need to distinguish here between a simple control system that can
automotive world put itself through hoops before realising open,
or at least public, standards are a much better idea - as did the
computer world (where would we be without ARPAnet?). I can't help
thinking that DCC is going to reach a "crisis" point sometime in
the near future and get re-invented (CAN sounds good)- and all
the current efforts will have been wasted.
provide several Amps of power and control over a pair of tracks, and a control
system that links multiple units together via a multi core cable.
DCC is an elegant solution to the first and irrelevant to the second.
I think the thing here is that the second you add a control cable that does
not involve the power aspect then there is no need to bother with the
restrictions of DCC, so perhaps a DCC2 is appropriate, but as a non-mobile
comms standard, keeping DCC for controlling vehicles on the track?
most applications, but only for reduandancy as such a use is considered
at least mission critical, if not safety critical) and is suprememly
immune to noise (i.e. dodgy contact with rails) etc, plus it is well
understood (it's used just about everywhere - including UK 12" to
the foot), decoders are two a penney and have built in sort circuit,
over-voltage and reverse voltage protection, and it works down to
6.5V (or similar, it was a while ago I used it) if it has to.
Two or four wires are still a cable! Lester is talking about the
difference between a cable and using the rail/wheel interface to make
That is the one :)
Neither CAN or Ethernet can carry POWER on the same pair as is used for the data, which is the whole point of DCC
If you are proposing to replace DCC to locos with CAN (or ethernet is
another one I've seen proposed) then you are onto a loser. The
environment is simply too noisy and error prone.
If you are proposing CAN as a layout control bus then it has already
been done by Zimo.
And given the price of USB modules, THAT would be fine for the hard wired control loop!
The bit of the jigsaw I'm not understanding yet is the return path from the locos on the track to the DCC controller. If you stop sending power for a period of time will we not have less power available at the loco? I'm personally thinking Gauge1 here where I need to get a power a long distance, and I can't see how the decoder can drive it's reply message back without having a powerful driver as well?
Lester Caine - G8HFL
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