I have an application where I require highly accuarate measurements of water temperature (see attached schematic). I work for a hydroelectric facility that is seasonally affected by cold water temperatures and frazil ice. In order to reduce the effects of frazil ice, we have to closely and accurately measure the water temperature at our forebay headworks as the water temp approaches 0.00 deg C. Our current system is now obsolete and requires replacement. We require 4 high accuracy sensors as illustrated with an accuracy near +- 0.001 deg C that would be able to provide a 4-20mA output. The operating range in which we're most interested is between -1 - +3 deg C.
Your assistance is appreciated.