４ - １０ Creating Alarms ４ - １０ - １ Alarm Mechanism Just as the conventional PTs, the NA has the function to manage alarms that give the users the warnings of errors and problems occurred in the machines. The NA’s alarm mechanism is prepared to combine the following two schems depending on the environment where the system is established. (1) Managing the alarm list/log on the NA side (HMI alarms) In the “HMI Alarms” scheme, the PT has the alarm processing function. Therefore, alarm management by the controller is simple. This scheme is often selected when multi-vendor support of controllers is required.
(2) Managing the alarm list/log on the NJ side (Troubleshooter) In the “Troubleshooter” scheme, the controller has the event processing function, and the PT only displays the events. This makes the entire management including the PT simple, and allows the users to reduce design man-hours. Therefore, this scheme is used for the system in which the configuration of NJ and NA is fixed. When the controller is changed, all the HMI alarm functions need to be remade. Troubleshooter ＨＭＩ Alarm Function Event Function Error Detection Program 49 Even though controllers are changed by the user’s specification, it does not matter if the alarm variables interface for the controllers remain the same.
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