Am 15.02.2017 um 08:25 schrieb Sven Giermann:
>
> I have several temperature sensors and 1 DS2423 counter in one room. All
> are connected with a Cat.5 network cable (about 30 meters) in a single bus
> that ends in another room with a small embedded Debian ARM (armel) server
> that runs OWFS 2.8p15-1.
>
Please update to 3.1p5. No one wants to hunt bugs fixed for years.
> Everything fine up to here. Let's call this branch "A".
>
> I then started to connect some software programmed ATTiny85 custom 1-wire
> slaves, drawing another branch (branch "B") from my server. That way, the
> first star-alike topology was built, currently a single bus, but with the
> master in the middle.
> This also worked for the first 2 devices, about 7 meters distance to the
> master (remember the additional 30 m to the other sensors). I used simple
> electric cable (NYM-J 3x1.5mm²) for this second branch, because I needed
> the third wire for some higher currents.
>
I would suspect the ATtiny slaves are a more picky about the timing then
the Dallas/Maxim ones.
> Well... some months later I added 2 more custom slaves on a third branch
> ("C"), having a typical star topology now with the master in the middle.
> Again, those are connected with NYM-J as well, with about 4 meters distance
> and..... yes, it worked!
>
> My problems started when I expanded the last branch by another 4 meters
> trying to connect a third slave on that branch!
> Suddenly all 3 slaves on that branch disappeared from the bus.
>
Yes. That could happen and it is likely to happen. The star topology is bad.
> I could not get them back, whatever I tried: removing the 4 meters
> extension, disconnecting the other 2 branches, only connect a single slave
> - nothing helped.
> (But they showed up and worked for weeks before I added the extension!)
>
> I then finished my setup first - having a total of 3 slaves on branch "B"
> and 7 slaves on branch "C". Branch "B" has a total length of 12 meters,
> branch "C" about 30 meters:
>
> Master (DS9490R)
> |--()--()--...--() "A", 30 meters Cat.5, 8 slaves
> |--()--()--() "B", 12 meters NYM-J1.5, 3 slaves
> |--()--()--...--() "C", 30 meters NYM-J1.5, 7 slaves
>
> Still, only all slaves of branch "A" and the the first two of branch "B"
> show up on the bus. For testing purpose I went and connected my laptop
> running a virtualized Debian installation and OWFS to that bus - and: ALL
> devices showed up and responded to read and write commands. It took some
> seconds and maybe 3-4 runs of 'owdir /uncached' to see all devices, but
> finally it worked.
>
No, it didn't. What you have is an extremely brittle setup which may or
may not work, depending on moon phase and other non-insightful
parameters. This is impossible to debug.
>
> Now... does anyone have any advice what to change/try next?
> Should I try to compile OWFS 3.1?
>
You should install the Rasbian package from the testing repository.
Testing(Stretch) has owfs-3.1p5. You can use the owfs packages
from the Raspbian testing repository. Edit (or create) your
/etc/apt/preferences to contain:
--------------------------------------------------------------------------
Package: *
Pin: release o=Raspbian,a=stable
Pin-Priority: 500
Package: *
Pin: release o=Raspbian,a=testing
Pin-Priority: 300
--------------------------------------------------------------------------
This is important so you keep stable (Jessie) for all packages but the ones
explicitly taken from testing (Stretch).
Then, add a line
--------------------------------------------------------------------------
deb http://mirrordirector.raspbian.org/raspbian/ testing main contrib
non-free rpi
--------------------------------------------------------------------------
to your /etc/apt/sources.list to get access to the Raspbian testing
repository.
Do an
$ sudo apt-get update
to read the package metadata, then check
$ sudo apt-cache policy
whether the testing repo is there with priority 300. Then
$ sudo apt-get update -t testing owserver ow-shell
That should install all you need, including the startup files and
systemd units.
Note you have to edit /etc/owfs.conf again to contain (this and only this)
--------------------------------------------------------------------------
!server: server = localhost:4304
server: w1
--------------------------------------------------------------------------
Restart the owserver service after that.
> Is there any configuration (defines?) that can cause different timing on
> the bus - making it work on i386 and fail on armel?
>
Do you use the DS9490 on both?
> Any advise to change the bus? Different cable? Different master (I have
> another LinkUSB)?
> Again: I already disconnected branches "A" and "B" resulting in no slaves
> at all - with a single bus/branch.
>
> Hope somebody can help me out...
>
First, get rid of the star topology. Make a lobe with the help of the
additional wires in the Cat.5 cable. Replace the 12m NYM-J1.5 stub by
another lobe cable with at least 4 wires. Connect your 30m NYM-J1.5 stub
to the far end of that lobe.
If you can't do that or don't want to do that, use multiple host
adaptors or a host adaptor with built-in switch e.g. the DS2482-800. Or
try to get two DS2409 switches.
Kind regards
Jan
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