Inclusion and accessibility in HMI

contrast adjustment in ABB DCS interfacesfor people with color perception limitations

Abstract

This article presents the adaptation of human-machine interfaces (HMIs) of the ABB Distributed Control System (DCS), with a focus on operators with dyschromatopsia. The methodology was structured in integrated stages, starting with the diagnosis of the problem reported by an operator who experienced difficulties in distinguishing colors on the operation console. Subsequently, accessibility tests were carried out in accordance with ISA-101, including alarm reading by priority, execution of commands using color-coded buttons, and interpretation of graphical indicators, all monitored by a multidisciplinary team from health, management, and automation areas. The mapping of critical aspects identified two main limitations: the difficulty in reading priority 1 alarms due to the low contrast between text and background colors, and the low perceptibility of the Last One indicator, caused by inadequate line thickness and tone. Based on this diagnosis, the automation team conducted an in-depth analysis of dyschromatopsia, considering scientific classification, prevalence, and normative references. Based on these elements, adequacy criteria were defined using ISA101, NR-17, and ABNT NBR ISO 9241. A change management process was then structured in the SAP SMS GM system, ensuring multidisciplinary coordination. The implemented solutions included increasing the contrast between text and background colors in priority 1 alarms and enhancing the visual representation of the Last One indicator. Post-change validation confirmed accessibility improvements without negative impacts for users without visual limitations, consolidating accessibility as a strategic and replicable practice in industrial systems. The solutions were incorporated into the Brasil Oil & Gas 6.1.0 library of the ABB DCS, enabling their application in other Petrobras units.