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How far can a one-wire device properly operate? — Parallax Forums

How far can a one-wire device properly operate?

LoopyBytelooseLoopyByteloose Posts: 12,537
edited 2006-02-24 05:50 in BASIC Stamp
Okay, I realize that SPI and I2C chips are intended to be on the same board as the processor, but One-wire advertises as a 'Micro-lan'.

Recently someone asked me·about using ten temperature gauges on a solar water heater that included pipe in a concrete driveway.· So we are talking meters, not inches.

Can anyone tell me how far a basic unit will go without repeaters or extra boost?

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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

Comments

  • Greg YorkGreg York Posts: 2
    edited 2006-02-23 16:49
    I realize you might have wanted a quick answer which is something like 227ft 6in, but I wonder if you have had a chance to take a look at the following documents from DalSemi / Maxim:

    http://pdfserv.maxim-ic.com/en/an/tb1.pdf

    and

    http://www.maxim-ic.com/appnotes.cfm/appnote_number/148

    The first document referenced is "Tech Brief 1 MicroLan Design Guide" and the second is "Application Note 148 Guidelines for Reliable 1-Wire Networks". I have had a chance to read these documents in the past, and the answer to your question seems to be "it depends". Things like what is driving the 1-Wire net, quality of wiring, topology of 1-Wire devices, etc...

    Hope this helps and is not obtuse...

    Greg York
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-02-24 05:50
    Well, I did go to Maxim prior to coming here.
    And I can back. Went to your referals.
    The document was a big help as it discusses lengths up to 100 meter.

    But generally, there are some limits with any device. A ball park·is nice for starters. I shelved my 1-wire thermometer because it seemed to be of very little additional use. Then I came across comments that said it was superior for distances.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 2/24/2006 5:55:08 AM GMT
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