CALIBRATION OF THE TEMPERATURE TRANSMITTER, RTD, THERMOCOUPLE, TEMPERATURE INDICATOR

AIM

To calibrate (i ) Temperature indicator, (ii) RTD, (iii) Thermocouple, (iv) Temperature transmitter.

EQUIPMENTS REQUIRED

a) RTD-PT100b) Resistance boxc) Oil bathd) Temperature indicatore) I-V converter

SPECIFICATIONS

Sensor-PT100

Temperature range= -50c to 200c

I-V CONVERTER

PROCEDURE

CALIBRATION OF RTD:

a) RTD -PT100 is placed inside the oil bath.

b) Oil bath is first set to a particular temperature using set temperature control.

c) Resistance of RTD at that temperature is noted from meter.d) Temperature is varied in steps and their corresponding resistance is

noted.e) Measured resistance is compared with standard resistance at

particular temperature and their errors are calculated.

WIRING DIAGRAM FOR RTD AND THERMOCOUPLE CALIBRATION

230v

rtd

t/c

CALIBRATION OF RTD

TEMPERATURE

STD RESISTANCE (ohm)

MEASURED RESISTANCE(ohm)

ERROR

% ACCURACY

CALIBRATION OF TEMPERATURE INDICATOR:

a) A resistance box is simulated as a RTD and it is connected to temperature indicator.

b) From the table, the standard resistance for each temperature within the range.

Power supply

Oil bath multimeter

c) The particular standard resistance is set in resistance box and corresponding temperature indicator is noted.

d) This procedure is repeated for various temperatures and indicator value is noted.

e) Thus the measured value is compared with the standard value and error is noted.

CALIBRATION OF THERMOCOUPLE

TEMPERATURE VOLTAGE(mv) ERROR % ACCURACYSTD MEASURED

CALIBRATION OF I-V CONVERTER:

a) First zero adjustment is done for 4ma to I-V converter, the output should be 0v.

b) If for 4ma, the output is 0v, then there is no 0 error or else the input is adjusted until we get the correct value.

c) After 0 adjustments, span adjustment is done for 20ma, the output should be 10v.

d) If the output is not 10v, adjustment is made until we get the correct output.

e) For 4ma-20ma, current is incremented in steps and corresponding voltages are noted down.

WIRING DIAGRAM FOR TEMPERATURE INDICATOR:

(230v)

p n 1

n l 2

CALIBRATION OF TEMPERATURE INDICATOR:

TEMPERATURE (0C)

RESISTANCE (ohm)

MEASURED TEMPERATURE(0C)

ERROR ACCURACY %

CALIBRATION OF TEMPERATURE TRANSMITTER:

I/P CURRENT (mA)

OUTPUT VOLTAGE (V)

ERROR ACCURACY %

MEASURED TRUE

Power supply

Temperature indicator

RESULT

Thus the following instruments were calibrated and accuracies are determined

a) RTDb) Thermocouplec) Temperature indicator and temperature transmitter.