Departmental Papers (CIS)

Document Type

Conference Paper

Subject Area

CPS Formal Methods

Date of this Version



The final version of this paper will appear in the conference proceedings published by Springer-Verlag in the series Lecture Notes in Computer Science (LNCS). The final publication will be available at

SAFECOMP 2010. The 29th International Conference on Computer Safety, Reliability and Security. September 14 - 17 2010. Vienna, Austria.


We present FBDTestMeasurer, an automated test coverage measurement tool for function block diagram (FBD) programs which are increasingly used in implementing safety critical systems such as nuclear reactor protection systems. We have defined new structural test coverage criteria for FBD programs in which dataflow-centric characteristics of FBD programs were well reflected. Given an FBD program and a set of test cases, FBDTestMeasurer produces test coverage score and uncovered test requirements with respect to the selected coverage criteria. Visual representation of uncovered data paths enables testers to easily identify which parts of the program need to be tested further. We found many aspects of the FBD logic that were not tested sufficiently when conducting a case study using test cases prepared by domain experts for reactor protection system software. Domain experts found this technique and tool highly intuitive and useful to measure the adequacy of FBD testing and generate additional test cases.


test coverage measurement, test automation, function block diagram, programmable logic controller



Date Posted: 14 July 2010

This document has been peer reviewed.