On 1/3/2012 07:32, Robert Conway wrote:
Hi List,
I am trying to re-establish my 1wire network again after a number of
months of it being taken down. Nearly went down an ardiuno/cloud
historian route however have developed too much on my web server to
start over again.
My biggest problem thus far has been reliability and the devices
(DS2409's) falling off the link, I have two hubs on the network.
Think I have tracked it down to a power supply used for the hub power.
Changed over the plug pack and seems to work better, fingers
crossed. I have the same 12VDC supply directly connected to both hubs
and only run DQ/GND between the Hubs.
The DS2409 offers 10 ohms of series resistance through its MAIN port and
about 13 ohms through the AUX port. On a long and perhaps more complex
network, particularly one that is parasitically powered, these add up
fast and can produce issues. Stick to the MAIN port if you can.
Moisture or other contamination will provide additional fodder for trouble.
As your network has been down for a while, you might then look at the
configuration of your hubs and the condition of the cabling and sensors
attached. If it is not directly powered, consider this to improve
reliability.
Green is not a good colour at wire and contact ends. I have seen this :)
I have on my network
2 x Hubs (Hobby Boards)
Humidity, UVI, Barometer (Hobby Boards)
DS18S20,DS18S20, DS 18B20 temperatures
DS2423 Counter
If I look at Bus/stats/errors I see no CRC8 errors out of 217 tries,
however am getting 30% error rate on the CRC16. Just started the
system back up as I did an upgrade to 2.8p14 and I see 39 tries and 14
errors for the CRC16.
What devices use CRC16 ver CRC8. ?
What do others people get in terms of errors on their
bus.0/statistics/errors ?
Is solid core or stranded CAT5 cable better ?
Stranded (patch) cable will have higher reliability in conditions where
there is flexing of the cable. You should have no performance
difference otherwise between these types.
Is shielded Cat5E cable any better, I suspect I would have to tie the
shield to earth at some point.
Shielding introduces awfulness in the form of increased cable
capacitance and the shield acts as a nice Shielding will break things
even more. However if you must use shielded cable I've read (but never
tried) that it's best to leave it disconnected at both ends. Same for
unused pairs. May I assume you use pair 4 and 5 as your OWIO and return
lines?
/m
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