Diagnosis messages are shown in the engineering suite Automation Builder. The diagnosis information can be accessed in the IEC application and can be forwarded to, e.g., a web server or a control panel.⮫ “Diagnosis in IEC application”

Diagnosis messages can also be read out from the display of the PLC.⮫ “Diagnosis messages”

Some diagnosis messages need to be acknowledged by the user (alarms +), others do not require acknowledgment (events +). The diagnosis system stores alarms and events in a diagnosis history.

Diagnosis messages include the severity of an error. Error severity can be used for defining system behavior, e.g., activating the error LED or stop the PLC.