DS18B20 all displaying 32*F

I'd been running 6 DS18B20's for 2 years reading temps in a saltwater tank and ambient air as well. Originally they were running parasitic, but later set them up powered individually. A couple months ago 1 of them died and started reading -196*F, but I already had redundancy so I hadn't replaced it yet. Today all of the temps read 32*F (0*C). In the past, this has happens every couple of months, I simply reboot it and then it's fine. But today no amount of rebooting, wire jiggling, what-not will fix it. If I pull the "one wire" while it's running they all got to -196*F.

It's been 2 years since I touched the code, and I know all sorts of things have changed, but I have to assume it's a hardware issue. Anyone have thoughts as to what I can look for?


corrosion of wires contacts pins of the chip, ...?



corrosion of wires contacts pins of the chip, ...?

I've seen zero corrosion anywhere but for the sake of argument, which wire would cause it to throw 32*F? If the 'one wire' is pulled it reads -196*F.

Would lack of power, from a corroded wire, to one or more cause the 32*F reading? I'll play around with the power side of things and see what happens. Also I've replaced the 4.7k resistor with no change.

When you were changing the wiring from parasitic to direct power, did you change the code as well? Please post the sketch you're using as well as links to the libraries you used.

Did you ever resolve this issue? I have the same thing all my sensors are reading 32F since i hooked them to the cat5 wire. Any help would be appreciated.

32F == 0C indicates no measurement

Did you use the Dallas Temperature Control Library to read the chip?

Please post your code.