# Supervision System 4.0 for a Road Tanker Washing Robot Manipulator
## 4 Simulation and Testing of the SCADA System  
Following the system development described in previous section, the fourth stage of development in the SCADA life cycle, known as \"operation\", was put into practice through testing the entire system. The most important aspect in a SCADA software project is approval by its users, who can assess its productivity and usability. To test the SCADA software, the virtual architecture described in Figure 8 was adopted. In this architecture, the Ignition server, in which the SCADA software is implemented, is connected to the PLC that controls the robot manipulator Digital Twin. The connection between the PLC and the Ignition server was carried out through the OPC UA communication protocol. Once the SCADA software was configured, its functionalities were tested on mobile devices that access the Ignition server through the HTTP protocol. 1. Validation of Supervision interfaces  
All the functionalities available in the HMI defined in Figure 6 were thoroughly tested, except for those related to alarms, which are discussed later in Topic 3. The tests include the introduction of parameters or the actuation of buttons in the HMI and the validation of the system by comparing the behavior observed in the Digital Twin with the expected behavior. For this validation, commands were issued from different devices, namely an HMI interface connected to the PLC via Ethernet, a smartphone and a computer connected to the SCADA server via the Internet using the HTTP protocol. The tests carried out validated the correct operation of the control and supervision services, as well as their usability in terms of navigation strategy and the visual arrangement of components in each synoptic. 2. Validation of communication in the SCADA system  
To validate the data exchange strategy, wash operations were issued through the supervision interface, and it was verified that the data stored in the database matched the desired wash configurations. The communication strategy was also validated by means of report generation based on data stored in the database by the SCADA system. To this end, the washes carried out by the DT and the alarms that occurred during its operation were registered in the database. Of the various available reports for this system, a report was automated that shows the various alarms that occurred during the one-week period. The consistency of the stored data and the data in the synoptic alarms and in the reports led to the confirmation of the correctness of the communication between the SCADA system and the database. The functions validated here allow the SCADA system to communicate with the other software present in the organization. It is enough to connect the organizational software with the database adopted for the development of the SCADA system. Figure 8: SCADA system architecture applied to the DT of the road tanker washing robot. Alarm service validation  
Verification of alarm signaling was performed by creating faulty or abnormal operating conditions. To this end, three types of situations were selected that exemplify the most common anomalies, specifically:  
No manhole detection--A situation where washing cannot proceed due to the necessary conditions not being met. To perform this test, the road tanker was removed from the DT model and a washing task was issued. As a result, the simulated image processing algorithm fails to detect a manhole. Communication failure--To simulate this event, a failure in the communication between the PLC and the robot X-axis control drive was injected in the DT. Safety fence crossing--This is a critical situation that leads to an immediate stop of the robot operation. To simulate this, a safety fence crossing event was injected into the DT. In all tests performed, the anomaly was successfully detected, and the corresponding alarm was triggered and displayed on the HMI interfaces. In addition, following an alarm notification, the HMI presented the operator with instructions to take the necessary actions to resolve the alarm situation.