Itech7410 Software Engineering Methodologies: Chcsv10 Assessment Answers

Assessment Details

The assignment requires you to produce an analysis report containing five components identified under the Assessable Tasks/Requirements.

Background – Central Heating Control System V10 (CHCSV10) Project

You have been retained as a Software Engineering consultant to the Heating2 Company. The company produces heating equipment for residential and non-residential facilities. Heating2 are planning to release a new line of gas fired central heating systems and need to have a new version of a central heating control system (CHCSV10).

CHCSV10 is installed in conjunction with the physical central heating system and automates and controls the heating processes. Your job is to oversee modelling of the real-time software required for the CHCSV10.

CHCSV10 will allow a single user to program, automate and monitor all aspects of the central heating of a facility. To achieve this, CHCSV10 requires the installation of other components of the central heating system including a heating unit, fan, gas supply, ducts and duct piping, temperature detector, clock, control panel and display.

Below is a schematic diagram (excluding duct piping) of an installed central heating unit package with WiFi connectivity.

Conceptually, the central heating system has two major components – CHCSV10 and the central heating system hardware sub-system. Some of the components of the hardware sub-system can be configured with either hard-wired or wifi enabled controllers. The decision is up to the customer and is generally based on the cost of the more expensive wifi controllers compared to the cheaper hard-wired controllers with additional labour and material costs of cabling. In the schematic diagram, wifi controllers are shown for the Ducts, Heating Unit, Heating Unit Fan and Gas Meter Supply. The controllers allow for two way communication (send commands/receive information) and control of the associated hardware component. Other components however - System Control Panel, System Temperature Detector, System Clock and System Display are usually connected physically with hard-wired connections.

A process of setup, installation and testing of all hardware components precedes the setup, installation and testing of CHCSV10 and is finalized by commissioning of the entire central heating system. The setup of CHCSV10 includes the setting of time periods and synchronizing of starting point for automatic controller messaging (see below). CHCSV10 facilitates all events of the central heating system including start up and stopping, configuration of the system clock, setting of heating programs, allowing manual heating, monitoring of components, displaying information about the system and actioning both system and manual events. Typically an owner of the system sets up the clock date and time, configures a set of program schedules for a day of the week and lets the system look after heating the premises. Further details of schedule examples and operation are given below.

There is constant communication between the other hardware components and control panel to monitor availability. Where necessary control commands are issued to these hardware components e.g. stop, start, open, close, make available, make unavailable. All communication and statuses from all components are displayed on the System Display. Further details about specific events for each external entity of the system are given below.

Detailed Description – Central Heating Control System V10 (CHCSV10) Project

As you might imagine this system would be quite complicated in reality. Where possible the description below attempts to simplify the system by stipulating assumptions and restricting scope.

Heating Duct

There can be up to 20 ducts installed in the top of the range system. In our example only four are shown and you should model just four. A Heating Duct blows warm air that has been generated at the Heating Unit and blown through all duct pipes by the Heating Unit Fan. A duct may be open or closed and these states can be set either by CHCSV10 or manually. If a duct is closed manually it can only be reopened manually. This is to allow for situations where a duct has been deliberately closed to an area. When the central heating system is operational, the Heating Duct Controller reports on the current state of the duct on a pre-determined periodic basis (in our case we will say every five minutes). The CHCSV10 system determines if a new status has been found and if it has displays that information on the System Display.

Assessable Tasks:

You are required to demonstrate an understanding of particular concepts covered in lectures, tutorials, laboratories and reading to provide the specification requested. This may require further reading and research beyond the material discussed in class.

Your task is to complete a Real-Time Structured Analysis Specification for the CHCSV10. You analysis should include the following components:

1. An External Entity-Relationship Diagram (ERD)indicating relationships of the CHCSV10 and the other external entities in the system. You do not need to include attributes of the entities on the ERD, just the relationships and their cardinality and modality.

1. Data and Control Flow Diagrams (DFD/CFDs) - to sufficient detail that only a single task is carried out byeach process at the lowest level (Do not however model the functionality of the System Clock - Configure and Set Time, Configure Temperature Detector, Set Heating Program processes; just have a process for each). You should show the control events/flows and data flows on the same diagrams. Use the real-time extensions for control flows etc shown in the lecture notes (slides 15-17 from week 3). You need to determine when and where events will occur. For example, whenever a piece of data becomes available it may need a control event to let the system know that it is available. These events must be clearly shown in these DFD/CFD diagrams and then handled in the CSPEC.

1. Process specifications (PSPECs) - a pseudo-code or similar design language specification is required foreach process at the lowest level. A narrative description alone will not be considered sufficient.

1. Control Specifications (CSPECs) - use combinational or sequential FSMs as required, presented in anappropriate format. The idea is that the CSPEC will completely describe how each and every event or control flow is handled in the system. You need to provide both "Process Activation Table" and "State Machine Diagram" as appropriate.

5. A Data Dictionaryis required to adequately describe each name or special term used in the analysis. This includes process names, data flow names, data stores, control flow names, control stores and events.

You should include sufficient detail to allow the system to handle all the monitoring and control aspects specified in the Detailed Description section of this document (and any further aspects you consider essential).