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temp=85 - power problem?

drzen

New Member
Hi,

in my house the free space for cables is minimal, so 1wire cables are near power lines :-( and every cable is about 6-8 mt. long.

I use a twisted 1 pair with shield (shield not connected). But I get some temp=85.

I suppose it is a interference problem or low power problem.

What do you think if I:
Solution 1:
1. get a power injector ( http://www.hobby-boards.com/catalog/links/...20Schematic.pdf )
2. connect
pin 2 of a rj45 (see http://www.hobby-boards.com/catalog/howto_wiring_diagram.php ) to shield
3. connect shield to VD0 (the 3 pin of DS18S20)

So DS18S20 has the +5v power via cable shield.

Solution 2:
1. get a power injector
2. use an unshield 2 pair cable?

solution 3:
Same as solution2 but with non-twisted cable.


Thanks for your help
v.
 

ericvic

Active Member
You are correct that the temp = 85 can be either noise on the line or a power problem but I have seen it more from noise so that would get my vote.

and every cable is about 6-8 mt. long.
How do you have your network laid out? If you have a star network and are not using a hub then that could be your problem.

Normal unshielded CAT5 cable is the best thing to use. I have heard that shielded cable can cause too much capacitance and you don't want to use non-twisted wire because that will reduce the rejection of noise.

Eric
 
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