Thermal Sensors Lab
In a processing plant, a chemical tower has a liquid which is vaporized.
However, if the vapor in the tower reaches 150°C, an alarm needs to be
generated so that safe shutdown of that system of the plant may be initiated.
An RTD will be used to measure the temperature of the vapor. The RTD will
generally operate between 80° to 175°C and has a resistance of 220? at 20°C.
The fractional change in resistance per 1°C is 0.0040. The dissipation constant
is 25mW/°C. Design a circuit to activate an LED alarm when the temperature
reaches 150 °C. The error should not exceed +/-1°C. Use a single supply
Draw a block
diagram for your design. Explain the function of each block and why it is
circuit showing all calculations. Choose standard resistor values, and specify
the tolerances. Provide a drawing of your circuit with all resistor values and
tolerances and parts. You may do this by creating it in Multisim and then
drawing the values on as appropriate.
circuit in Multisim using the resistor values you chose and tolerances. Do a
screenshot showing how you have set up the tolerances for the resistors. For
the RTD, you may use a potentiometer or variable resistor for which you can
change the resistance for different temperatures. If you have a bridge circuit
with a potentiometer for nulling, explain how you decide what resistance to use
for the null.
Create a table
of temperature, RTD resistance, RTD resistance adjusted for self-heating, LED
Status. Test your circuit, and use the table to display your results. Find the
precise resistance and temperature at which the LED turns on. Provide several
screenshots showing the resistance which reflects the RTD resistance value used
in the circuit and the LED alarm. Which RTD resistance do you use in the
circuit for testing?
Put together all
of the above in a well-written report including introduction, requirements,
block diagram, design calculations, final design (including any potentiometer
settings), testing (including which RTD resistance is used in the circuit for
testing), and analysis of results. Be sure to provide a summary at the end,
noting at which temperature the alarm was activated, if this was as designed,
and what accounts for differences. Please note any problems you encountered.
report as EE372W3LYourGID.docx (or other word processing document). Save your
Multisim file as EE372W3LYourGID.ms. Submit both documents.