Design Pattern: PF(4) Secondary level of detail


Within his area of responsibility and authority, the human operator needs to comprehend sets of incoming alarms displayed by alarm displays. After getting an overview of the status of the controlled process in his area of responsibility the human operator would like to access to a more detailed information.


The human operator needs to access to a more detailed information in order to better understand the status of the controlled process in his area of responsibility.


Use secondary level of detail that presents all the alarm information regarding key elements of specific units or areas of the controlled process. This secondary level of detail allows operators to execute common and critical abnormal situation interventions. This level should be composed by a set of alarm selective displays, which show more detailed alarm information. It should also provide support displays, such as trend displays, diagnostics, calculation details, and so forth.

Known uses
Fig1. ASM-style secondary level display
Fig2. ISA-style secondary level display

A secondary level provides more detail to support what is already known or suspected from viewing the first level. If the overview looks normal, examining the secondary displays can be queried to verify this. (Rothenberg, D. H. (2009). Alarm management for process control: A best-practice guide for design, implementation, and use of industrial alarm systems McGraw-Hill Education.)