## 3 Application for Testing a SCADA System Operator Knowledge  
The engineering method for testing product quality within the process of assessing the education quality of a SCADA system user presented in the article is employed within the knowledge testing application. An application testing a SCADA system user (operator) is a practical tool for testing skills and knowledge. It should be again emphasized that is has been developed in a graphical environment of the SCADA Intouch suite [10; 11], which is used by the operator in everyday work. It is a crucial aspect since a tested user (operator) is not required to become familiar with an additional testing suite. He/she conducts the test using a SCADA system visualization suite, employed during professional work as part of the control supervision process at the operator station. Therefore, the trainee may--in the event of an experience user (designer, engineer)--focus on the process of diagnosing own knowledge. On the other hand, in the case of diagnosing a different user (e.g., system operator candidate), the trainee's fluency in handling the SCADA suite is an additional hint for the examiner that proves mastering practical skills. The application is of modular structure (Figure 14). This indicates that, depending on the user type, it can operate in the examiner and/or trainee mode. To distinguish between the users, it is required to authenticate them using an ID and password. The trainee ID and password are set individually for each position. Windows to be displayed are customized from the SCADA system level and additionally (for improved security) via an introduced flag system. The test taker is distinguished by first and family name, work number, and position. The user interface structure enables bringing up successive visualization windows, depending on the selection made in the previous step. Figure 14: Modular structure of a system operator testing application. Figure 13: Dependence of the credibility index on the grade accuracy (i.e., number of grading levels). Logging in to the module enables the examiner to perform two types of administrative actions (Figure 15):  
* configure test parameters directly prior to starting the test;
* operations related to the question database at the preliminary test configuration stage. When operating the testing application, users encounter two types of activities: Operational and performance related. They start with logging in (registration and user authentication) to the application. Operational activities are conducted from the administrator-examiner level. The set of operational activities implemented from the examiner module has been marked in Figure 16 in blue. These include operational activities listed in the Figure 15 diagram, along with the final approval--which is the direct preparation for launching the proper test that verifies the knowledge of a SCADA system operator. Whereas performance-related activities--from the perspective of testing application operation--are conducted by a trainee. These are steps required to take the test and include confirming readiness to take the test, providing answers to subsequent questions, and learning the result shown after completing the test (shown against a yellow background in Figure 16). Figure 16: Operational and performance-related activities of the SCADA system operator testing application operation. Figure 15: Configuration—options available from the examiner (system administrator) level. A window for the trainee and examiner modules is displayed in order to enable setting test parameters (Figure 17). Virtual buttons selected out of the ones visible in the \"settings\" window are available for each of these two user types. Figure 17 shows an examiner module window with the option to edit all parameters available in the synoptic screen. It enables single- or multi-station application functioning. Certain preparatory actions are required in the case of both single-station and multi-station work. These include, among others:  
1.