Originally Posted by bobotwf
The DS18B20s aren't RTDs. They're ICs that use the 1 wire protocol. Each chip has a separate address and they're all connected to the same data pin on your microcontroller. They don't provide a change in voltage or resistance or anything with temperature. I use them and highly recommend them, they're easy to work with and mine were very accurate.
Yep, you wuz right. I know you know you were right, but you know how men are.
The other one I bought was the proper one and all is well now. I'm in $10 for two sensors, one of them worked. so not too bad. Here's what I ended up getting:Probes Unlimited Pt100 Temperature Sensor RTD Automation Controller Teflon Probe
This shows it as a two-wire but it is a three wire so .. not sure but whatever it works and is within a couple tenths of matching a calibrated sensor setup so all is well in the world. Excellent service from this company, very fast shipping if anyone else has the need.
I used to do
building controls but have been out for a long time having decided to stay with just the IT side of the house. My brew buddy is still in controls thankfully so he was able to get me straightened out.