Quote Originally Posted by carl_e View Post
Given the way an RTD works - a constant DC current is generated by the analog input and pumped through the resistance of the RTD to develop a voltage drop which the AI 'sees' and interprets as a temperature - you'd better hope that the construction of an RTD isolates the RTD element from the sheath, otherwise ground loops will develop and the ground loop current running through the RTD element will give false IR drops which in turn will give false temperature values.

An RTD element is typically suspended, insulated and electrically isolated from the sheath by mineral insulation, typically MgO.

The RTD element's wires exit the sheath at the "transition" and various manufacturers do transitions in various methods.

For answers to your other questions, Google is your friend.
thank you..!! can you please tell me how exactly the RTD element is connected to the sheath.? you said it does not touch the sheath. then how is it attached,?
and also i want t know how th RTD element, sheath, thermowell and the process pipe are all connected to each other.? i mean by welding/flange or any other means.?
thanks..!!