Flow Charts and Control Systems

Transcription

1 Term 1 Grade 11 -Task Sheet 2 Teacher s Guide Flow Charts and Control Systems Picture 1 Picture 2 Page 0 of 6

2 Task Sheet Unit 3 OBJECTIVE To create a flow chart to design a control system. You will be covering the following Student Learning Outcomes (SLO) Create a flowchart to design a system Design a control system using inputs, actions and outputs Explain the difference between a closed-loop control system and an open-loop control system EQUIPMENT REQUIREMENTS Laptop or Computer, pen, pencil, ruler SAFETY REQUIREMENTS N/A TASK INTRODUCTION Scenario A vending machine is filled with disposal water bottles. To get one water bottle, buyer can only use 25 Fils, 50 Fils or 1 Dirhams coins in the machine. A buyer can get more than one bottle at a time. Using the flowchart symbols, draw a flow chart in the workspace given below. List all the inputs, actions and outputs for the vending machine control system. Identify the vending machine control system classification [open-loop or closed-loop] and write any two differences between open-loop and closed loop control systems. Task Guidelines Students read the callout instructions provided for guidance. Page 1 of 6

3 Draw your flow chart here Start Put the coins in the machine NO Are coins accepted? YES Press the selection button Is item present? NO YES Collect the water from tray YES Want more water? NO End Page 2 of 6

4 Work Plan No. Work Steps Step Completion & Values Remarks 1 Flowchart A start symbol is used to start a flow chart. START I can draw this symbol 2 A symbol for input and ouput is used Input / output 3 A symbol for processing is used process 4 A symbol for decision making is used decision 5 Data flows were used to connect all the symbols 6 Vending Machine Inputs (Answers may vary, but should relate to appropriate inputs, actions and ouputs for a vending machine system) Input for vending machine is identified. Coins I can identify the input for a system 7 Vending Machine Actions Actions for the vending machine system are identified Go to place where vending machine is present Put the coin in the coin slot Press the number required using the selection buttons 8 Vending Machine Outputs Outputs for the vending machine system are identified Stock checking Deleiverying the water to the tray Calculating the balance Page 3 of 6

5 9 Vending machine is a closed-loop system because a buyer can get as many water bottles as he requires until the money balance is there. Open-loop / Closed-loop 10 Comparing Open and Closed-loop systems Open-loop and closed loop differs in many ways (Answers may vary. Students are supposed to write only two differentiation, but try to discuss all the points listed.) Open-loop 1. Feedback element is absent 2. An error detector is not present 3. It is stable one 4. Easy to construct 5. Very cheap 6. It is inacurrate 7. Less maintainace Closed-loop 1. Feedback element is always present 2. An error detector is always present 3. It may become unstable 4. Complicated contruction 5. It is costly 6. It is accurate 7. More maintainance A Vending Machine System for reference Page 4 of 6

6 A Check of Dimension and Function No. Points Student Teacher 1. Flow chart symbol start, flow and terminators are used Flow chart symbols and descriptions for input and output are used. 3. Flow chart symbol and descriptions for processing is used. 4. Flow chart symbols and descriptions for decisions are used. 5. System inputs, actions and outputs are identified. 6. Feedback loop is identified. 7. Open and Closed loop advantages and disadvantages are rightly mentioned Maximum Achievable Points 7 B Visual Checks Summarization of Actual Points No. Inspections Explanation Student Teacher 1. Students could use the necessary flow chat symbols. Check for the flow chart drawn 2. Students could understand the feedback system Check for the feedback system chosen 3. Check for the Students could differentiate the comparison between Open and Closed loop control the open and closed systems loop control systems Maximum Achievable Points 3 Summarization of Actual Points maximum points A X 70 % maximum points + X 70 % maximum points A X 30 % + B + maximum points = X 30 % B Page 5 of 6

7 A Check of Dimension and Function Marking Rubrics No. Points Flow chart symbol start, flow and terminators are used. Flow chart symbols and descriptions for input and output are used. Flow chart symbol and descriptions for processing is used. Flow chart symbols and descriptions for decisions are used. System inputs, actions and outputs are identified. 6 Feedback loop is identified. 7 Open and Closed loop advantages and disadvantages are rightly mentioned B Visual Checks No efforts made Student had used the right symbols for start, stop and data flow. No efforts made Student had used the right symbols for input and output and had filled the inputs/ouputs for the system No efforts made Student had used the right symbols for processing and had filled with system processing details No efforts made Student had used the decision symbol and filled the decision details for the system No efforts made Student had identified the inputs, actions and outputs for the control system No efforts made Students rightly identified the feedback system No efforts made Students were able to compare and differentiate an open and closed loop system No. Points Student could use the necessary flow chat symbols. 2. Student could understand the feedback system 3. Student could differentiate the Open and Closed loop control systems No efforts made Student had presented a neat flow chart diagram No efforts made Student had circled the right loop system No efforts made Student had differentiated the open and closed loop control system. Page 6 of 6