Book Creator Add this page to your book Book Creator Remove this page from your book Manage book(0 page(s)) Help This page is not fully translated, yet. Please help completing the translation. (remove this paragraph once the translation is finished) MES-Terminal interlocks Three Boolean variables are required. Variable Type Description Direction HeartbeatToMES BOOL Blinker signal from PLC in three-second cycle (maximum 3 sec. signal pause and maximum 3 sec. signal) From PLC to MES HeartbeatToPLC BOOL Blinker signal from MES to PLC From MES to PLC EnableMachine BOOL MES set this variable. The machine may only start automatic mode if this variable is set to TRUE. Attention: If the status of HeartbeatAnSPS does not change for e.g. ten seconds, EnableMachine has to be ignored. From MES to PLC Signal status diagram 'MES terminal interlocks' The pulse can be generated either by the PLC internally or in TC2/3 by the block MES_Lifebit. Section 1: Machine gets release from MES-Terminal. Section 2: MES-Terminal withdraws machine's enable (the next cycle should not be able to start). Recommendation: If EnableMachine = FALSE and the next cycle should be started, there should be a PLC error message, e.g. “Machine has no release from MES-Terminal”. Section 3: Use case “Production without MES system”: If HeartbeatToPLC is not written, the machine is released as failover. HeartbeatToMES HeartbeatToPLC EnableMachine Is machine enabled? Toggle Toggle TRUE TRUE (see section 1) Toggle Toggle FALSE FALSE (see section 2) Toggle FALSE TRUE FALSE (not possible) Toggle FALSE FALSE TRUE (see section 3)