Lab2_Level Control

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Sheridan College *

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1067

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Mechanical Engineering

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Dec 6, 2023

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Page 1 of 5 Sheridan College Faculty of Applied Science and Technology ENGI 24495 – Control Systems Lab 2 – Level Control Name: __Shubham Ghai________________, Student #: ___9916614111 Name: __Yashpreet Singh_____________, Student #: ___991661790 Name: ____Jasnam Singh_______________, Student #: _____991666471 Name: __Jashanpreet Singh Student #: ___991657832 Name: __Jashanpreet Singh Mann_______, Student #: ___991665172 Name: __Jaideep Singh _________________, Student #: ___991662751 Introduction: This lab explores the characteristics of level control system. Students will be familiar with the level trainer and measuring the level using different instruments. The Level Control Trainer is a closed loop system designed to demonstrate industrial control technology. The variable to be controlled using this system is the water level in a level tank. There is a pneumatically activated valve which serves as the actuator in the control circuit. The water level is determined by a pressure transmitter. A submersible pump is used to force the water flow in pipelines. Using the outlet cock, an experimenter may simulate disturbances and adjust tank drain rate. You should complete the pre-lab exercises in your lab report before coming to lab. Then carry out the inlab exercises during the lab session. After completing the in-lab exercises, have the instructor check your work and sign your lab report. Finally, complete the post-lab exercises in your lab report, save the lab report as a pdf file, and submit it to the relevant Assignment on Slate. The lab report is due one week after the lab session . Pre-Lab Exercises: 1. For the level trainer shown below, use the manual to identify the parts and fill out Table 1.

Page 2 of 5 Table 1: Layout of the trainer Item # Description Item # Description 1 Level cylinder with intake, outlet and overflow 6 Control valve (driven pneumatically) 2 Level sensor (pressure transducer) 7 Filter/ pressure regulator unit 3 Outlet cock (for setting disturbance) 8 Switch cabinet with E-Stop 4 Pump 5 Tank with inspection glass In-Lab Exercises: 1. Turn on the trainer. 2. Turn on the computer connected to the trainer and allow the desktop screen to load. Locate the Level Control Trainer icon shown below. Set the computer data and time to the experiment data and time. 3. Click the above icon to launch the software and to load the start- up page. Then click the “Push to Start Lab” button to open the home page. 4. Click the “PI&D” button to see the layout of the machine. 5. Hit the “Home” button at the top right of the screen to return back to the “Home” page. 6. Select the “P&ID Trend” button on the home screen, to record data during this experiment. This will be the main page that is to be used during the experiment. From this page, you can start and stop the pump using the Green “Start” and Red “Stop” buttons at the right side of the screen. 7. Set the set pint (SP) to zero, Proportional gain (Kp) to 1, Integral time (T I ) to 10, and Derivative time (T D ) to zero. Swi tch on the pump by clicking the Green “Start” button. Wait until the system reaches the steady-state condition.

Page 3 of 5 8. Gradually increase the set point by an increment of 10 cm up to 50 cm and record the level gauge readings in Table 2, manual reading column. Every time you increase the set point, you should wait for the steady-state condition of the process output. 9. Switch off the pump by clicking the Red “Stop” button on the right side of “P&ID Trend” page. 10. From the home page, click the “Data” button to sho w the collected data during the experiment. For data analysis, click the “Export Data” button on the bottom right of the screen. This will export the data to an Excel file on the computer desktop. If you cannot locate the exported data file, you may copy t he data from “Data” page to an Excel file. 11. Save the Excel file to your USB drive or email it to yourself. 12. Turn off the trainer and the computer. Post-Lab Exercises: 1. Open the Excel file and plot the set point and output measurements. Copy the graph to the lab report, in the space provided below. 221, 30.23113 230, 36.28169 -10 0 10 20 30 40 50 60 0 50 100 150 200 250 300 350 400 450 500 Level (CM) Time (Sec) Level Control System Set Point Level

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Page 4 of 5 2. Fill out Table 2 where actual reading is the output level in steady-state condition from Excel file and the error is calculated as: 𝑀𝑎??𝑎𝑙 𝑟?𝑎?𝑖?𝑔 − 𝐴???𝑎𝑙 𝑟?𝑎?𝑖?𝑔 𝐸𝑟𝑟?𝑟 % = × 100 𝐴???𝑎𝑙 𝑟?𝑎?𝑖?𝑔 Table 2: Comparing manual and actual readings. Set Point (cm) Manual Reading Actual Reading Error (%) 10 10 10.3 -3% 20 20.5 20 3% 30 31.5 30 5% 40 42 40 5% 50 53 50 6% 3. Discuss the different sources of errors in Table 2. 1. Sensor Accuracy: Inaccurate level sensors can introduce errors. Ensure that the sensors used to measure the liquid level are calibrated correctly and have a low margin of error. 2. Environmental Factors: Temperature, pressure, and other environmental conditions can affect the fluid properties and, consequently, the level. These should be accounted for or controlled. 3. Human Errors: Errors in setting up the experiment, data recording, or improper operation of the control system can introduce errors. 4. Dead Time: Delays in the system's response due to factors like sensor lag, signal transmission time, or valve response time can affect control performance. 5. Equipment Wear and Tear: Aging or damaged components, such as sensors, valves, or controllers, can lead to inaccuracies. 4. Calculate the time constant ( 𝜏 ) of the level system from the Post-Lab Exercise 1. Please note that the time constant of a process is the time required for the process output to change to 63% of the step input. Show your work. Tau = 63% Output Time – 0% Output time Tau = 230-221 Tau (Time constant) = 9 Sec.

Page 5 of 5 5. Discuss the importance of the time constant ( 𝜏 ) in system measurement. Time Constant is crucial as it determines the system’s response time to changes in Level. Longer time constant indicates slower response which is inefficient and Shorter time ensures optimal performance. Time constant tunes PID system in the model.