Am Sonntag, 17. September 2006 12:34 schrieb Philipp Haeuser:
> So far, I've found out that it's often the sensors at the end of the
> longer branches that cause problems. As a proper 1wire "switch" would
> cost as much as all my current 1wire hardware together, this is not
> really an option for me right now. I'll have to compromise for the time
> being, as I'm also unable to rewire the sensors.
>
Hm. Really? I would encourage you to try a lobe wiring instead of the switch.
It's an option only if you could use 4 wires per sensor cable, though.
Sensor1 Sensor2
/\ /\
|| ||
|| ||
HOST------/\------/\---...
As long as the total cable length is not beyond 500m, that should work better.
> I will try to cut down wire lengths and implement a higher-level "retry"
> mechanism with time backoff in my scripts, and I'll just have to live
> with a bit of instability - 3 or 4 errors per day even without any
> retries ( I assume that owfs does not attempt any retries in that
> situation ) is not that bad, after all :)
>
Yes. That's perfectly reasonable, as owfs AFAIK currently doesn't implement
automatic polling.
> Does anyone know whether moving the DS9097U adaptor really close to the
> hub, i.e. to have 80 feet of serial port cable instead of 80 feet of
> 1wire bus, would help in my situation?
>
> I know that an 80 feet serial port cable is no problem at all if it's
> a regular null-modem link between two PCs, but the question is whether
> the reflections etc. caused on the 1wire bus by my flaky setup would
> just propagate to the serial port cable, too... ?
>
With the DS9097U, it could be a problem that this adaptor is powered through
the handshake lines of the serial port. A long cable may cut to much voltage
from these lines on the way. This depends heavily on the wire gauge.
BTW: feet? I would feel more comfortable if you stick to SI units here.
Kind regards
Jan
--
1) Never draw what you can copy.
2) Never copy what you can trace.
3) Never trace what you can cut out and paste down.
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