Instrumentation Measurement & Lab
Temperature Alarm Project
The team project encompasses week 7 and week 8 assignments. You will begin working on this project as a team in week 7 and continue to week 8. You will turn in your final project in week 8.
Project Structure:
In general, you will have one other classmate in your team. Each of you will design and simulate an instrumentation circuit with different specifications though you will choose and use the same sensor. Thus, it is highly suggested that you communicate with your partner as early as possible to plan and coordinate your activities, select the specifications for your design, and establish a schedule. For the testing phase, you will develop a test plan and characterize and validate your teammate's circuit.
During the project period, you are encouraged to communicate, exchange ideas, and help each other complete your project. A team area will be set up for you in Blackboard, and you are required to use this area as part of your grade will be based on effectively using this tool. Do NOT use your personal email for communication. If you use your phones or Skype, you must have meeting minutes which you post in the group area.
Each of you will submit your own Multisim file and report, which will include an evaluation of your teammate's cooperation.
Project Definition:
The objective of this project is to design a temperature alarm system which measures air temperature and provides an alert when the temperature exceeds its defined upper and lower limit. Specifically, a red LED should turn on when the temperature is lower than the lower limit or higher than the upper limit. When the temperature is between these two limits, a green LED should be on, indicating that the temperature is "normal."
The options for the lower and upper limits are as shown below. Each teammate should pick a lower and upper limit, and these should be different than those of anyone else in the group.
Lower limit options: 40, 50, 60, 70 ?
Upper limit options: 80, 90, 100, 110 ?
The design will consist of multiple stages as shown below in Figure 1. Note that a thermistor is to be used. Also, for the "Amplification Circuit" block, use an operational-amplifier wheatstone bridge (your team will need to find this on the internet and discuss how to properly use it in your design). For the thermistor, you should use the internet to find a thermistor you want to use and use its datasheet. Teammates must use the same thermistor. A possible alarm circuit is shown in Figure 2. Don't forget to use commonly available parts.
Project Simulation:
Once you have designed the circuit, build it and simulate in Multisim using tolerances, and then pass it to your teammate to test it.
Write a test plan and test your teammate's design. Be sure to demonstrate that the specifications are met below the lower limit, in the normal range, and above the upper limit.
Project Troubleshooting Manual:
You and your teammate should identify one problem that could cause your design to malfunction and write a short step by step process for a technician in the field, starting with the output symptom, to troubleshoot the circuit and identify how to fix the problem. Assume that the problem is not with the power supply (supplies).
Project Deliverable: Report and the multisim design for your project
Each student will submit an individual report. The report should, as a minimum, include the following:
- Title Page (Name, Partner's name)
- Description of your project (including the specifications you selected)
- Conceptual Design: Explain the block diagram and what each block does (its functionality) and how it works. Also, be sure to explain when one might use an operational-amplifier wheatstone bridge and its advantages.
- Design methodology (show calculations and provide rationale for design choices; remember that your choices must take into consideration commonly available parts).
- Final schematic in Multisim
- Components/Parts list
- Simulation results for your design
- Testing process and results for characterization and validation of your teammate's design - screenshots alone will not suffice. Description of process is required along with discussion of results.
- Troubleshooting Manual for one potential problem
- Project Challenges: Note any difficulties you faced during the completion of your design and how you overcame them
- Team Interaction Reflection: Describe how you used Blackboard to facilitate interaction, how you worked with one another in the design phase, challenges you encountered, methods you employed to overcome any challenges.
- Teammate Assessment: Use the Project Participation Rubric below and give your teammate a ranking of Needs Improvement, Competent, or Excellent for the first two items in the rubric: Interacts professionally and Plans and organizes team effort. Be sure to justify your ranking.
- Conclusion
- References
- Data sheet for thermistor
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(Yourself):
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Ranking
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Reasoning
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Interacts Professionally
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Plans and Organizes Team Effort
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Teammate Name:
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Ranking
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Reasoning
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Interacts Professionally
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Plans and Organizes Team Effort
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Teammate Name:
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Ranking
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Reasoning
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Interacts Professionally
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Plans and Organizes Team Effort
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PROJECT PARTICIPATION RUBRIC
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EXCELLENT
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COMPETENT
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NEEDS IMPROVEMENT
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Interacts professionally with team members - cooperative, respectful, shares ideas and work load, completes tasks on time
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Performs work on time; attends all meetings on time; participates in timely fashion in asynchronous collaborative efforts. Listens and responds appropriately. Encourages other points of view. Openly shares information. Receptive to feedback. No complaints from any of the team members.
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Performs work on time; attends all meetings and participates in asynchronous collaborative efforts but may be occasionally late in attendance, providing information or updates. Listens and responds appropriately. Shares information but may require prompting. Minimal complaints from other team members.
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Is sometimes late in providing information or updates; or may miss meetings; or shares information but often requires prompting; or is unreceptive to feedback; or fails to consider other viewpoints. Numerous complaints from other team members.
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Plans and organizes team effort including roles, work distribution, and collaboration tools
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Actively participates in development of team objectives, planning, and organization, including roles and tools. Quick to identify own knowledge and skills applicable to the project and contributes in assigned role.
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Participates in development of team objectives, planning, and organizing though some prompting may be required. May not understand the planning phase well but values the process. With help, identifies contribution which can be made and fulfills assigned role.
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May not value the planning and organizing process and the establishment of roles; or struggles in how to fit into the project; or depends on others to fulfill assigned role.
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10. Conclusion
Instrumentation Measurement & Lab
Midterm
1. A temperature sensor is exposed to a sudden change of 20oC to 80oC. The sensor outputs 0.02 volts for every oC of temperature and has a 2.3 second time constant.
a. What is the sensor output voltage at 1.5 seconds?
b. At what time, t, does the sensor output become 1.0 volt?
2. A sensor, R, that changes resistance is used in a bridge circuit as shown below.
a. What sensor resistance, R, will null the bridge?
b. What is the off-null voltage if R changes by 0.5 Ω?
3. A measurement system has noise above 20 kHz and the data signal frequency is between 100 and 500 Hz. Design an RC filter that reduces the noise by 95%, i.e., only 5% is left. Show the schematic and the component values.
4. Given a Type J TC with a 25oC reference.
a. What is the temperature if the TC voltage is 22.87 mV?
b. What voltage would result from a temperature of 225oC?
5. A 10-bit ADC has a 5.00-volt reference.
a. What binary output is produced by an input of 3.04 volts?
b. Suppose the output is found to be 1F4h. What is the possible input voltage?
6. A 12 bit bipolar DAC has a 10-volt reference.
a. If the hex input is 5D7h what is the DAC output voltage?
b. What input is required to get a zero volt output?
Week 8 Final Exam
Instrumentation Measurement & Lab
Final Exam
1. A golfer estimates that his golfball is 250 yards to the hole. At the hole, another golfer has dropped a water bottle that is reflecting light back to the golfer and his ball. What is the approximate time difference based on golfers distance to the hole/water bottle?
2. A CdS photocell has a resistance versus light intensity as shown in the following graph. The cell has a time constant of 25 ms. At t=0, the cell is exposed to a sudden change of light intensity 20 W/m2 to 80 W/m2. What is the sensor resistance after 20 ms?
3. A force of 120 pounds-force is used to open a valve. What is the area of the diaphragm if the pressure difference is 90 kPa (~ 13 psi) that must provide this force?
4. A processing plant is being proposed and will need to use of the city's water system to be sucessful. The plant will need a minimum of 2500 gallons of water per minute (gpm) for its operation. The city's current water supply pipe to the proposed plant is 12 inches in diameter with a water velocity of 1.5 m/s. Will the city's current water supply meet the plant's needs or will it need to be upgraded? Show calculations to verify your answer.
5. From the figure below, construct the truth table for the logic diagram. What function does this represent?
Figure 2.