WHAT IS RTD?

Learning's:

1             1.  Dust Collector

2. Level sensor

3. Fire Sensor Alarm

    4.  Resistance Temperature Detector

    5.  Load cell

    6.  Magnetic Contactor

    7.  Weight Feeder

8. Limit switch

9. Solenoid valve

10. Thermocouple

11. Actuator

12. Pyrometer

13. Compressor

14. Weight feeder 

15.    VSD

                                     WHAT IS RTD?

Ø  RTD means Resistance Temperature Detector

Ø  operate on the principle of changes in electrical

Ø  resistance of pure metal and characterized by

Ø   linear positive change in resistance with

Ø  temperature. typical elements used for RTD

Ø  Include nickel and copper, but platinum is by far

Ø  the most common because of its wide temperature

Ø  range, accuracy, and stability. RTDs are popular

Ø  because of their excellent stability, and exhibit the

Ø  most linear signal with respect to temperature of

Ø   any electronic temperature sensor. they are

Ø  generally  more expensive then alternatives,

Ø  however because of the careful construction and

Ø  use of platinum. RTDs are also characterized by a

Ø  slow response time and low sensitivity; and because they require current excitation, they can prone to self-heating.    

                                        CLASSIFICATION OF RTD

Ø  Wire base RTD are three kind.

Ø  1.Two-wire.

Ø  2.Three-wire.

Ø  3.Four-wire.

Ø  Temperature base RTD are two kind.

Ø  1.Positive temperature co-efficient.

Ø  2.Negative temperature co-efficient.

                         Resistance Temperature Detector

An RTD (Resistance Temperature Detector) is basically A temperature sensitive resistor. It is a Positive& Negative temperature coefficient Device.

                                        PRINCIPLE OF RTD

Ø  The RTD is composed of certain metallic elements whose change in resistance is a function of temperature. In operation, a small excitation current is passed across The elements, and the voltage which is proportional to resistance is then measured and converted to units of temperature calibration.

Ø  The RTD element is made from a pure material platinum, nickel, or copper. The material has a predictable change is resistance as the temperature changes it is this predictable change that used to determine temperature.