To all those 1-wire weather station starters…
After weeks of chasing bugs and wild geese I have managed to now produce, what appears to be, a functional and stable 1-wire microlan with Weather Display and WDL.
Winedog,
Why are you using a hub? I have a one wire system using a DS9097U (much weaker than the link) with Rain gauge, weather station, lightning detector, barometer, 3 humidity senors, and 5 temp sensors and it runs perfectly without a hub. I’m curious why some 1-wire users are using hubs? Am I missing something?
Hi,
This microlan was developed for a winery that needs outdoor weather sensors, temp/humidity for the barrel room, and temperature for the fermentation room. All places being at oppossite ends of the buildings. If I tried to to create a linear topology there would be significant cable lengths for each of the drops. I suspected that this would not work so decided to implement the network with a HUB. Take a look again at the cable lengths on my microlan diagrams and that should clarify why a star topology was more appropriate for my microlan implementation.
Don’t get me wrong…if you can do a linear microlan you’ll always have less trouble…and if the HUB didn’t work for me, I would have started trying to repatch everything into a linear topology, but that would be messy and I had serious reservations about power on such a long linear microlan with long drops to individual sensors.
Badger, badger, badger, badger, badger, badger, mushroom, mushroom
I have stacks of trouble with my hub if I put any of the sensors on the hub, i get the sensors reading weird values, sometimes it doesn’t pick up the sensors and sometimes it colapses the entire network.
Got any suggestions as to what might be causing that?
the hub is a switching device
and so the software has to switch channels on, read the sensors, switch that off again, switch the next channel on, read those sensors, switch that channle off again, etc,
maybe i dont have that working correctly (quite likely)…I dont have a hub here…
I thought the hub was supposed to be transparent to the software reading the lan?
Actually, I don’t think the HUB is transparent to the software. When using some of the utilities from AAG you can actually control the opening and closing of the various switches on the microlan. So it does appear that software has some degree of control over the HUB as Brian indicated.
While my microlan now appears quite stable, I still can see an occasionaly anomaly with the order in which ROM IDs are recognized and on which HUB port they appear on. This might be where WD needs some fine tuning to work with the HUB…but for now it seems to work fine for me. I’ll be experimenting with adding another segment / radial of temperature sensors this week. I’ll let you know how that goes.
yes, the hub does nothing if not controled by software…
its switching device, and has extenal power…means you can prevent interactions of devices…
but in reality 1 wire stuff is supposed to live happily together…and a well designed one should work OK (but external power source seems like a good idea)
Brian, maby its worth trying to see if you can get a hub. I have noticed some strangeish things when the hub is in use. The software dosent allways pick up the correct sensors on the correct ports, and even when there is nothing on the ports it still manages to find things on the ports some how.
winedog,
I’ve been using a 1-wire lan and WD for about 4 years. I don’t use a hub but I do use CAT5E in a linear topology with “branches” of 60-100 feet in length. I use the iLink adapter and it has solved a number of issues related to 1-Wire LAN noise, timing, and other problems. The iLink adapter, by far, has been the most effective addition to my 1-Wire LAN problems. Concerning CAT5E wiring, I use only two wires from the cable, one conductor from each of two different pairs ( cuts down on capacitance, the bane of 1-Wire LANs). I also do not use any external power for devices. Works ok for me.
Your information is great! Wish I’d had it when I started my 1-Wire LAN.
geewizard,
Thanks for your post! Wow! That’s great to hear that it will work with branches that long! Good to know! If my HUB approach failed that was my next step, but I was worried that I would still have problems. However, from your setup it sounds like that is a feasible topology.
Between your approach, the use of a HUB, or running multiple instances of WD in combination with extra USB 1-wire adapters, it seems like the options for success with 1-wire microlans in a variety of topologies and size are much better than I originally thought.
Just out of curiosity how have you joined your branches onto your main cable lead? Solder? Junction boxes?
winedog,
I use 3m Scotchloc UR connectors outside to connect the wind instrument, rain gauge, humidity sensor, and barometer together. All are Dallas/AAG products. You can usually get them locally or from Digi-Key. Here’s a description URL:
http://www.tselectronic.com/3m/ug_ur_uy.html?tse_Session=7a1cd0ad8eb4e6a63dbff021b327939b
The Scotchloc connectors are all stuffed up into a plastic milk jug with the bottom cut out. See: http://apsn.awcable.com/weatherstation.jpg
Inside the house, I solder all connections. I think, as I stated in my previous post, that the solution to my problems with noise, cable problems, and signal timing on the 1-wire LAN were solved when I replaced the standard AAG serial adapter with the iLINK adapter. I can’t stress this enough. I looked at my LAN with an oscilloscope and saw how terrible the leading and trailing edges of the data pulses looked. The iLINK deals with all that just fine.
(addition: when I bought my iLINK, it was called that. Now on AAG’s web site, it’s called The Link).
Good luck with your 1-Wire setup. I think it’s a really neat system to use.
Love that picture Geewizard! Very clever work! Good to know that those UR connectors are doing the job on such long cable runs…I love those little UR connectors!
Thanks again!