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Software Testing for Pattern Approval

Measuring instruments used in commercial transactions are more and more developed as network systems controlled by complex software. In order to check the system properties with sufficient depth and in an adequate period of time a software tool was developed enabling analysis and testing of complex measurement systems by simple application of the manufacturer documentation.

The software tool X-Ass developed by PTB will simplify the pattern testing of complex measurement systems which are to obtain the CE mark.

In pattern testing of software controlled systems it is no longer sufficient to check the measurement correctness by traceability to standards. To an ever increasing extent the tests have to comprise an assessment of protection from manipulation and the conformity of the pattern with the individual production unit. With the new software tool the tester analysing an unknown system will be provided with a systematic instruction for the drawing-up of a model of the hardware components, e. g., subassemblies, and of the software. Accordingly, a total model of the measurement system will result considering the close interdependence of hardware and software. By this data flow analysis the flow of the measured values between the instrument components, inside the components and in the data domains of the software is tracked and illustrated as a so-called data path.

The set-up of the data paths is undertaken step by step. In parallel to each incremental step on the data path the tester will infer from the manufacturer documentation the partial function processing the measured value which is linked to the incremental data flow. By this guidance through the documentation of the measurement system supported by the software tool only the information relevant to the test will be selected. Thus quite different documentation forms may be effectively analysed.

The requirements applicable to the testing of the measurement system are stored in a data base specific of the measuring system. Parts of the tests, e. g., the functions required for the measurement task, will be automatically performed. All the other tests will be carried out in a dialogue with the tester on the basis of check lists. Finally a test report will be automatically generated and all the data characteristic of the measurement system will be secured so that these will be available at short notice when modifications to the instrument under test will be made at a later date. PTB is presently preparing for the use of the software tool in tests for EC and national pattern approvals.

Contact at PTB:

Phone: +49-531-592-0