Abstract
The safety system, the construction of which is based on the principle of safety (confirmation), permits the machine to start operation when it confirms that the "conditions of safety confirmation" have been met. However, it should be avoided that the machine stops operation automatically when the safety system fails to confirm the meeting of the conditions of safety confirmation. Similarly, it should also be avoided that the machine starts operation before the safety system confirms the meeting of the conditions of safety confirmation. Accordingly, such control is required that can set the conditions of safety confirmation based on the relevant information and operational performance. In 2013, the authors proposed a fail-safe interlock system for pneumatically driven systems. This interlock system, designed to realize safe failure, is equipped with a sensor as a pressure monitoring system utilizing window characteristics, a window comparator, and a shutoff valve having non-symmetrical failure mode characteristics. In this paper, referring to a pneumatically driven system as an example, the authors study regulatory control that can set the conditions of safety confirmation for pressure control by making the most of the relevant information and operational performance with the interlock system of their proposition used as a stopping mechanism and a monitoring function.
