Another DS18B20?

Go To Last Post
4 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi
I want to know what is the maximum cable length of DS18B20 device?

Thanks in advance.

I love Digital
and you who involved in it!

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

With the given information, the answer is something like "it depends."

What kind of cable? What is cable capacitance? Do you plan to give the sensor data and ground only, or also supply power separately? What is the supply voltage? Who is the master and what kind of IO stage it has? If an AVR, some things like excess capacitance may be compensated in software.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I want to use twisted pair cable it will contain vcc gnd and data all conectet to my avr.

I love Digital
and you who involved in it!

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Maxim has an appnote about using 1-Wire over CAT5. I think you find your answer there.

Or alternatively you could connect your temp sensor directly to AVR and insert capacitors until you are out of specifications. Then convert that capacitance to meters of CAT5.

Here is the link though :
http://www.maxim-ic.com/app-notes/index.mvp/id/148

So I'd say 100m. 200m-500m if you pull data line high.