# IoT-Aware Architecture to Guarantee Safety of Maintenance Operators in Industrial Plants
## 8 Discussion  
The described prototype has been deployed and tested in a real industrial plant based in central Italy. During the tests, an operator was asked to reproduce the maintenance procedure described in the previous Section, and, at the end of all the tests, the safety manager of the plant, who was supervising the procedure, was interviewed to identify the real benefits that our system can bring in a real industrial environment. Therefore, based on the feedback received by the safety manager, the present section discusses all the advantages that the proposed solution can provide to the community by analyzing the fulfillment of all the requirements reported in Section 5. As declared by the safety manager, if an operator lubricates the axes of a machinery by exploiting our system (as done in the tests) it is possible to guarantee the respect of the following safety measures:  
* drastically reduce the reasonably foreseeable misuse of machinery as disciplined by ISO12100--Definition 3.24. Specifically:
* Usually, people never correctly apply LOTO procedures (e.g., locks are not used, compressed air is not removed, or sometimes the presence of unauthorized operators outside the control of maintenance service operators to speed up the service is exploited). Our system allows real-time monitoring of its correct application so, for instance, if an operator tries to turn the compressed air on when it has to \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Involved Components** & **Taken Actions** & **Background Processes** & **Advances over the SoTA** \\ \hline - MwISM (mechanism that verifies the switch off) - Backend Server (APIs to receive status & & NFC used to: - Verify presence of operator in right position to authorize next step (lubrication) & Currently delegated to the self responsibility of employee \\ - Mobile App (NFC for presence detection) & & & \\ \hline - Mobile App & & - App verifies operator position \& that all steps were correctly followed & Currently delegated to the self responsibility of employee \\ - Mobile App & & Operator: & correctly followed & \\ - Backend Server (APIs to receive status \& mechanism to support verifications) & - Closes machinery door & - SS enables real time control of energy removal, door & Currently delegated to the self responsibility of employee \\ - MwISM (switch on Smart Service mode) & & Modal Selector ” (SS) & closing \& in case, activates emergency stop & \\ - Service & & - NFC verifies that no other operator is in same area & & \\ \hline - Mobile App (tabs to give instructions \& NFC for presence detection) & & - NFC used to: - Maintenance operator is not allowed to activate verify that no other operator is in the same area & - Maintenance operator is not allowed to activate any machinery component \\ - MwISM (mechanism for verifications) & - Absides the control station - Allows operator to chat with administrators for axes movements verifications & is in the same area & or movement through \\ - Backend Server (APIs to receive status \& mechanism to support verification) & with administrators for axes movements verifications & - Limit the set of axes movements that are available only through smartphone for maintenance verification & - Current procedures are difficult/impossible to be fulfilled \\ \hline \hline - Mobile App (NFC for presence detection) - MwISM (mechanisms for verifications) - Backend Server (mechanism for for orchestrating interactions & Operator: - Deactivates the “Smart Service Modal Selector” (SS) - Unlocks the machinery relevant energy sources in off position by removing the mechanical lock - Turns on the machinery - Ends the procedure & - NFC used to control operator position & Currently delegated to the self responsibility of employee \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._be off, the system enters the \"emergency status\", stops anything until an intervention is performed, the Smart Service mode is automatically disabled and the communication between the smartphone and the machine is closed.