13-03-2014, 04:57 PM
[u]Software Requirements Specification For Elevator System Controller [/u]
Elevator System.docx (Size: 438.23 KB / Downloads: 13)
Introduction
Purpose
The purpose of this document is to provide a consistent and complete description of the requirements for the software of an elevator controller. The requirements will be presented using textual descriptions to explain concepts, different types of diagrams to illustrate complicated interactions, and tables to relate relevant information. The intended audience of this document is all of the stakeholders for a project involving the development of elevator controller software. This includes, but is not limited to, software developers, project managers, quality assurance personnel, and customers.
Scope
The software of the elevator controller is responsible for the safe and efficient operation of all of the other components within the elevator system. The controller’s main goal is essentially to handle input signals from other components and respond accordingly with output signals. Two of the main computational obligations of the controller are to have a queuing system to log and process requests from passengers and to navigate the cabs of the elevators between floors in response to those requests. One of the other important objectives of the controller is ensure the safety of the passengers using the elevator system at all times. This is achieved through the interaction with certain components dedicated to monitoring environment attributes that are important to safety.
Overview
The rest of this SRS document contains all of the requirements for the elevator controller presented in several ways and organized into different sections. Section 2 contains general information that is not too specific and is provided as a background for the following sections. It contains descriptions of all of the other elevator components that the controller interacts with, as well as a context diagram that illustrates the entire elevator system. It also lists product functions, constraints, and assumptions about the controller. Section 2 is a good section for customers to read. Section 3 contains more detail and presents the requirements with many different diagrams that illustrate the functional requirements of the elevator controller. Some of the types of diagrams that are used here include, sequence diagrams, state diagrams, and collaboration diagrams. There is also a part of this section that describes the interface between the controller and the rest of the elevator system as a set of signals. Section 3 is most suitable for developers and testers. Section 4 of the SRS contains supplementary information required to complete the document’s breadth. It includes tables of all of the functional and non-functional requirements, as well as a table for each use case of the elevator controller. Both the requirements and the use cases are cross referenced with each other to provide traceability among both types of artifacts.
Product Functions:
• Controls the speed of elevator engines in order to move elevator cabs up and down their respective shafts.
• Queues and processes elevator summons and floor requests from passengers through the signals provided to it by several buttons.
• Processes information sent to it by load sensors in order to ensure that the load of a cab never exceeds the safety limit.
• Processes information sent to it by position marker sensors in order to keep track of where the elevator cabs are at all times, as well as their speed.
Hardware Interface-Application Program Interface
This SRS only pertains to the requirements of the software of an elevator controller, not the hardware that it runs on. Therefore, the details of hardware interface requirements are out of the scope of this document. That being said, the elevator controller hardware must provide a means of sending and receiving communication signals from other components of the elevator system in order for the software to be able to function properly. These signals are listed in the section below. They are simply invoked or handled by the controller software based on if the signal is input or output,