how to measure temperature from resistance of rtd?and how to measure temp from

how to measure temperature from resistance of rtd?and how to
measure temp from voltage of thermocouple?is there any formulas?

Question Posted / santhu.janga

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how to measure temperature from resistance of rtd?and how to measure temp from voltage of thermocou..

Answer / amit

Temperature measurement.

With RTD:
The Material used Is Platinum Which is very Sensitive to
the temperature as the temperature Changes the Resistance
changes.Which is next connected to form a Weatstone bridge
in the transmitter then According to the formula
R1/R2=R3/R4 since R2,R3,R4 are Constant So Change in RTD
Resistance R1 The Corresponding mA Signal is Obtained
through the transmitter to the system in control room.

With T/C:
Were As T/C is the Formation of two diffrent Material
Combined to form a T/C(SEEBACK EFFECT)As they r two
different materials Change in temperature Causes the change
in EMF generation between the two materials,This mV Signal
is then Transmitted to Marshelling cabinet to Convert it
into V because all Digital Signal read minimum 5V,it is
Converted by OP-Amp with 250ohm Resistance Across it whict
is convinient to DCS to read it.

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how to measure temperature from resistance of rtd?and how to measure temp from voltage of thermocou..

Answer / nishat

to measure temperature through RTD there is a formula T=(R-100)/.385

FOR PLATINUM RTD rise in 1 degree there is increase of 0.385ohm resistance

about T/C IF ANYONE KNOW SO PLEASE DO ANSWER

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how to measure temperature from resistance of rtd?and how to measure temp from voltage of thermocou..

Answer / jaywant joshi

During the measurement of Temperature from RTD, we have to
just disconnect the RTD from the control room,(as it is
externally powered, in case of thermocouple it is self
powered transducer) after disconnecting just measure
resistance of element e.g. 115 ohms.. then deduct 100 from
it...you will get say 15,,,then multiply this by 2.5..you
will get the temperature ,,approximately you will get 38
degrees..

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