Specification and Verification of Time Properties in Distributed Automation Systems during Test Planning Phase

Abstract

Test cases for distributed real-time systems are described with time-dependent cause-effect graphs including communication channels, messages and time requirements. The specification of time requirements for a test object uses time limits and intervals. In early development phases test reliability can be improved by means of configuration specification of a test object. The configuration consists of test object structure, node processing times and transmissions times between nodes. This information delivers more accurate data for test planning. This paper describes the specification of time properties in test cases, in test objects and their verification. It includes the selection of the communication paths between considered nodes. The transmission times between nodes are calculated dependent on transmission line parameters. In summary processing time along the communication path is calculated. The time comparison considers min/max values of time requirements and min/max processing time of the test object. This approach is universally valid and belongs to the class of white-box system testing. The procedure was approved for master-slave systems in a building security system.