Results 1 to 10 of 10
  1. #1
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,140
    I have put together a small network for my own training purposes. I have an Ilon100, Distech EC-67, SLTA-10, Circon VAV UHC-202 and hopefully some Echelon IO modules.
    My question is, do I need to buy a $25 terminating resistor or is there another way to do this? I installed some Trane controllers today and they simply use a resistor at the end of there 'LonTalk' comm. network. I think 105 ohm. Will this suffice? Thanks guys.

  2. #2
    Join Date
    Nov 2004
    Posts
    226
    Are you absolutly sure they only use a resistor?
    From what I can remember that EOLR "tunes" the channel absorbing reflections ect. the only solid state compoenent that can "absorb" anything electrical is a capacitor and to be sure a resistor. Echelon has a document that discribes the EOLR compoenents and you could make one I guess, but IMO just buy a few you will use them by the hundreds eventually.

  3. #3
    Join Date
    Feb 2005
    Posts
    345
    For a small desktop network, you're probably fine. Try it and see how the error rate is. If you can talk to the controllers and poll them for real-time values, you're good to go. If the error rate is high, you need to terminate the network.

    Niiko

  4. #4
    Join Date
    Mar 2005
    Location
    Fargo, ND
    Posts
    86
    Try it without ant termination at all.
    We have some Honeywell Lonspec systems out where we removed all the terminations and the system ran better.

  5. #5
    Join Date
    Nov 2004
    Posts
    226
    Ok,
    The system ran "better" can you elaborate please. Did you examine bus trafic with a protocol analyzer and see a scientic, quantifiable improvement?

  6. #6
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,195
    A small network will work fine without the terminator. Several I know of were put in without terminators - I added them later - and I put in one myself - 10 total Lon stamped controllers and I forgot to put in the terminator. It's been operating fine for over 4 months. It's over 200 miles away, otherwise I would have went back and added it.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


  7. #7
    Join Date
    Apr 2005
    Posts
    104
    'Tis true. For small networks, you don't really need to use a terminator (it is still good practice though, especially if the network is 200 miles away).

    Please refer to Chapter 4 of the following link if you are interested in making your own terms:

    http://www.echelon.com/support/docum...8-0156-01G.pdf


  8. #8
    Join Date
    Mar 2005
    Location
    Fargo, ND
    Posts
    86
    Originally posted by jimmyj
    Ok,
    The system ran "better" can you elaborate please. Did you examine bus trafic with a protocol analyzer and see a scientic, quantifiable improvement?
    Non-scientic perhaps, but there were many missing nodes with the terminating resister(s) in place as recomended. We removed them and now have zero problems monitoring the system. Plus before we were getting strange problems with zones and air handlers. Zones that would not heat or cool as needed, plus problems with the economizers. all disappeared after we reomoved the terminations. The system was "flakey" before, afterwards solid as a rock.
    Good enough for me!

  9. #9
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,140
    Thanks for the replies guys. My initial thought was to try to get away without the terminating resistor until I was on the job where Trane spec'ed a 105ohm resistor on their comm loop. That seems to be a cheap solution.
    Thanks for the link dude. That terminator is simple enough to make. I will probably try that route

  10. #10
    Join Date
    Sep 2004
    Location
    SoCal
    Posts
    446
    A TP/FT-10 channel (twisted pair) terminator is not just an end of line resistor, it includes a capacitor or two depending upon the channel topology. A single terminator is required for free topology. Bus topology requires a terminator at each end. I know, this stuff just works, - who needs em? Hell, I've seen it work on thermostat wire! Just not very well! So, if you are going to grow your LON and you want to keep it green (sorry, I can't help it)- you should be keeping the packet error rates as low as possible and this means using the right wire and the right terminators installed in the right places. And if you are doing LON without a protocol analyzer - you're shooting in the dark - like troubleshooting without a meter. Read chapter 4 in the FTT-10A user guide http://www.echelon.com/support/docum...efault.htm#OEM - it even gives the spec's so you can make your own Arnold and save the 20 bucks they cost. (here in
    Cali - we call him the Governator)
    Cheers,
    lb
    A hundred million nodes - it's a LON story.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event