Itech7410 The Central Heating Control Assessment Answers

The purpose of this assessment is to provide students with the opportunity to deepen, extend and apply the knowledge and skills developed from the first 3 weeks of material. Students complete the assignment individually.
As described in this course’s third study guide - Software Analysis, Modelling and Specification - there are two main
approaches to systems analysis specification – structured (or classical analysis) and object-oriented analysis. Your text, Software Engineering: A Practitioners Approach (Pressman, 2010) identifies these two paths as different approaches to requirements modelling.

There are special extensions to the structured approach to deal with real-time systems. Study guide three identifies a
real-time system as “…a system that has to respond to external events in a pre-defined maximum time interval. Hence
such systems differ from the normal software system in that their temporal performance forms part of their requirements”. 

 

The following course learning outcomes are assessed by completing this assessment:
S1. Critically analyse and use complex decision making to research and determine the appropriate Software Engineering tools and methodologies to utilize in a given situation
S2. Apply professional communication skills to support and manage the engineering of a large software system
S3 Review, critically analyse and develop artefacts to define processes for quality assurance, risk management and communication in large software development projects
S4 Implement quality assurance activities in order to verify user requirements and validate design decisions
A1 Analysis of a large system development problem to decide upon the best methodological approach

Data Flow Diagram (DFD): -

In this diagram, the user set the commands by using a system display. There are some commands: -

• Configure and set time
• Configure Temperature Detector
• Set Heating Program
• Manually Change heating
• Resume Automatic heating
• Turn system on /Off

Control Flow Diagram (CFD): -

This control flow diagram shows how the whole system works. This diagram does not show only central heating unit processes. It also displays the each and every unit flow to work when the system on.

Process Specification (PSPEC): -

Pseudo Code:

Below is the Pseudo code for my Central heating Unit. The process begins by checking the scheduled time and current time in the Unit. If the current time is in range, the System will start checking the status of components step by step. If at any step it founds that any component is not functional, it will stop the started components also and Display the corresponding Error message on Display Unit. It will first start with checking the temperature by Temperature Detector. If the temperature is below the minimum allowed temperature, it will try starting the gas Supply after checking its status.

If the gas supply is started successfully, it will start The Heating Unit, then Heating Fan and after that the Ducts. If at any step it fails to start that component it will stop the started components also, and display the error message. If all these steps complete successfully, the System is started and a message 'Central Heating Unit is Functional NOW' is displayed on the display Unit.

Central Heating Unit

1. Start
2. Record User Input on the Display Unit
3. set flag = status of Central heating Unit
4. if flag = 'OPERATIONAL', go to step 7
5. Display 'Central Heating Unit is not OPERATIONAL'.
6. go to step 999
7. check Inputs for Functional Schedules
8. set time=SYSTEM_TIME from system Clock
9. if time in Scheduled_Time, go to step 10
10. go to step 4
11. set flag = Temperature from System Temperature Detector
12. if flag > least temperature, go to step 14
13. Display 'Temperature above required, go to step 4
14. set flag = status of Gas from System Gas Controller
15. if flag= 'Available' OR flag='Operational', go to step 18
16. Display 'GAS is NOT Available for Central Heating Unit to Work properly.'
17. go to step 4
18. set gas Configuration and start Gas Supply
19. set flag = status of Heating unit from Heating Unit Controller
20. if flag= 'Available' OR flag='Operational', go to step 24
21. Display 'Heating Unit is NOT Available for Central Heating Unit to Work properly.'
22. Stop Gas Supply and reset its configuration
23. go to step 4
24. set Heating Unit Configuration and start it
25. set flag = status of Heating unit Fan from Heating Unit Fan Controller
26. if flag= 'Available' OR flag='Operational', go to step 31
27. Display 'Heating Unit Fan is NOT Available for Central Heating Unit to Work properly.'
28. Stop Heating Unit and reset its configuration.
29. Stop Gas Supply and reset its configuration
30. go to step 4
31. set Heating Unit Fan Configuration and start it
32. set flag = status of Ducts from Duct Controller
33. if flag= 'Available' OR flag='Operational' and Ducts_Available > 50%, go to step 38
34. Display 'Ducts are NOT Available for Central Heating Unit to Work properly.'
35. Stop Heating Fan and reset its configuration.
36. Stop Heating Unit and reset its configuration.
37. Stop Gas Supply and reset its configuration
38. Display 'Central Heating Unit is Functional NOW'
39. END

Control Specification (CSPES): -

• Process Activation Table: -

Process Activation table
S.NO.	Occurrence of event	Activated process
1	Central Heating System Turn On	Gas Unit Controller
2	Gas supply meter Turned On	Heating Unit Controller
3	Heating Unit Turned On	Heating Fan Unit Controller
4	Heating fan Unit Turned On	Ducts Unit Controller
5	Ducts Open	Start Heating
6	Central heating System Turned Off	Turn Gas, Heating Unit and Heating Fan Unit ducts Off

State Machine diagram: -

Data Dictionary (DD): - 

• Gas supply meter controller: - gas supply meter controller id controller the state of the gas meter, on/ off, operational or not operational etc. When central heating system operational then gas supply meter controller displays the current state of gas supply meter on the system display.
• Heating unit controller: - heating unit system controller control the heating unit states, heating unit capacity and when central heating system operational then heating unit controller displays the current state of the heating unit on the system display.
• Heating Fan unit controller: - heating fan unit controller control the state to heating fan unit, circulation capacity and when central heating system operational then heating fan unit controller displays the current state of heating fan unit on the system display.
• Ducts controller: - ducts controller control the ducts state and when central heating system operational then ducts controller display the current state of ducts state on the system display.

Bibliography

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