Hi Eloy

"Eloy Paris" <[email protected]> wrote in message 
news:[email protected]...
>
> I do find it very odd that things work perfectly when the LinkUSB is
> connected to a laptop but don't work when the LinkUSB is connected to
> another machine because the 1-Wire network is connected to the LinkUSB,
> not the computer the LinkUSB is connected to. You could try talking to
> the LinkUSB directly using minicom (on Linux) or HyperTerminal
> (Windows). Hit the 'h' key to get help for the basic commands (you can
> ask the LinkUSB to reset the bus, to find sensors on the bus, and do
> other things like send commands and read responses. The idea would be to
> see if the LinkUSB resets or something, but I doubt you'll see anything).

I was doing this, minicom on Linux and Putty on Windows. The percentages 
were
estimates based on 'f' commands and how many responses were an 'E' or
the device ID. The errors were so numerous that it wouldn't generally show 
up
with owfs because the device searching failed.

A scope should show more about the signals, but I briefly used the LA which
showed that part of the CRC during a search ROM was corrupted in the case I 
captured.
I wondered about reflections on the bus.

The power was from the LinkUSB. Behaviour was the same
whether parasitic or powered. It seemed odd that powering the a breadboard
with PIC would improve things. I didn't try removing the PIC to see if was
actually the buses on the breadboard that was making the difference.

So at the moment with one sensor on the end, the 10K pullup and wiring as
detailed before, while there are a few CRC errors and very occasionally the
device disappearing, reading the device every 5 seconds works almost
100% reliably. I did notice the device went while a fan in one of the 
toilets was
running, which may be coincidence but I need to check that our of interest.
I'm also going to try running a machine not on a UPS too.

I also introduced a powered 4 port USB hub to connect the link to
which made no difference.

The most critical change though was definitely switching to using the 
white/blue
earth rather than white/orange.

Our PC's and phones are connected to a gigabit switch and we have 3 phase 
power.
I assume being plugged into the network wouldn't cause any earth related 
issues but
might try disconnecting that just to see. Being able to cut the network at 
home
and splice in a new slave without really any problem (fewer than 0.002% CRC 
errors
at the moment) makes me feel lucky now though.

If I get any more results from tests I'll post back. I'll be adding spurs
with a few PIC and 18b20 slaves and I'm expecting that will probably make it
mostly if not completely reliable as a result, but we'll see :) 



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