Design Pattern: RM(7) Flashing


A set of incoming alarms has been registered. The human operator would like to both detect and distinguish them from alarms that have been accepted.


The human operator needs to be made aware of new incoming alarms, which have not been accepted yet.


Show new incoming alarms by using flashing. An 'off' condition should never be used to attract attention to an alarm message. Flashing should not be used as a means to highlight routine information. It should only be used as an alerting code. When a user must read a displayed item that is flash coded, an extra symbol such as an asterisk or arrow to mark the item should be used, and the marker symbol should flash rather than the item itself. No more than two flash rates should be used.

Known uses
Fig1.Top priority alarm stand out by using flashing in DeltaV control system
Fig2.Use of flashing to visualize the status change of an alarm in the Proface control systems

Flash coding generally reduces search times, especially in dense displays (Zhu, J., Zhuang, E., Ivanov, C., & Yao, Z. (2011). A data-driven approach to interactive visualization of power systems. Power Systems, IEEE Transactions on, 26(4), 2539-2546.)