How IEC 63303 Redefines State-Based HMI Display Strategies

flowchart LR
    A["IEC 63303"]:::blue --> B["HMI Philosophy"]:::green
    B --> C["4-Level Hierarchy"]:::blue
    C --> D["State-Based Displays"]:::green
    D --> E["Faster Response"]:::red
    classDef blue fill:#2563eb,color:#ffffff
    classDef green fill:#16a34a,color:#ffffff
    classDef red fill:#dc2626,color:#ffffff

When an operator stares at 400+ process variables during an abnormal event, response time depends entirely on how the HMI presents information. IEC 63303:2024, published by IEC Technical Committee 65 in August 2024, provides the first international normative framework for IEC 63303 HMI design in process automation. It builds upon the established ANSI/ISA-101.01-2015 methodology while introducing stricter lifecycle requirements and compliance pathways that apply globally to continuous, batch, and discrete processes.

What IEC 63303:2024 Covers and Why It Matters

Before IEC 63303, global HMI design practices relied primarily on the US-centric ANSI/ISA-101.01 standard published in 2015. While ISA-101 remains foundational, it operates as a framework rather than a normative specification. IEC 63303, developed by IEC Technical Committee 65, Subcommittee 65A (System aspects), closes that gap by providing a more normative international standard with testable compliance criteria.

The standard defines the general structures, functions, and performance expectations for HMI systems across their entire lifecycle. It covers philosophy definition, display design, implementation testing, commissioning, ongoing operation, and maintenance through to decommissioning. Unlike vendor-specific HMI guidelines, IEC 63303 is intentionally generic and applicable to any process automation system that uses an HMI to interface with a control system.

The IEC 63303 Lifecycle Model

IEC 63303 structures HMI management into distinct lifecycle phases with continuous processes running alongside them. This lifecycle approach prevents the common pitfall of treating HMI design as a one-time commissioning task.

flowchart TD
    subgraph lifecycle ["IEC 63303 HMI Lifecycle"]
        A["Specify"]:::blue -->|Philosophy and Style Guide| B["Design"]:::blue
        B -->|Task and User Analysis| C["Implement"]:::green
        C -->|Build, Test, Train| D["Operate"]:::green
        D -->|In-Service Monitoring| E["Maintain / Decommission"]:::red
    end
    subgraph continuous ["Continuous Processes"]
        F["Management of Change"]:::blue
        G["Audits and Validation"]:::green
        H["Performance Metrics"]:::red
    end
    D -.->|Triggers| F
    F -.->|Feeds Back| B
    G -.->|Informs| D
    classDef blue fill:#2563eb,color:#ffffff
    classDef green fill:#16a34a,color:#ffffff
    classDef red fill:#dc2626,color:#ffffff

The Specify phase produces two documents that every compliant facility needs: an HMI Philosophy document that captures design intent and operational goals, and an HMI Style Guide (or toolkit) that standardizes symbols, color usage, fonts, navigation patterns, and alarm behaviors across the entire system.

The 4-Level Display Hierarchy

Both ISA-101 and IEC 63303 define a structured display hierarchy that limits the amount of information shown at any given time. Instead of cramming every process variable onto a single P&ID mimic, the hierarchy distributes information across four progressive levels of detail.

The hierarchy works because it mirrors the cognitive flow of operator decision-making. An operator checks the Level 1 overview to detect a problem, navigates to Level 2 to localize it within a process unit, drills into Level 3 for equipment-specific diagnosis, and uses Level 4 only when deep data analysis is required.

Most organizations starting an IEC 63303 implementation begin by redesigning Level 1 and Level 2 displays, since these screens deliver the highest return on operator situational awareness improvement.

Grayscale-First Color Strategy

One of the most counterintuitive principles in IEC 63303 and ISA-101 is the restriction on color usage. Traditional SCADA displays use vivid colors throughout to represent piping, equipment types, and normal states. High-performance HMI inverts this approach entirely.

In a compliant design, the display remains visually quiet during normal operation. Equipment outlines, piping, and process schematics use neutral gray tones. Color is reserved exclusively for abnormal states and items requiring operator action. When a pump trips or a temperature exceeds its setpoint, the relevant element shifts from gray to a defined alarm color. This approach works because the human visual system detects color changes against a neutral background far faster than it can distinguish one bright color from another.

“The interface should remain visually silent during normal operations. Information should be presented in a way that highlights anomalies immediately without competing with decorative noise.” — ISA-101.01 design principle, reinforced by IEC 63303

State-Based Display Switching for Abnormal Situations

Static displays treat every operational state the same way. A startup sequence, steady-state production, and an emergency shutdown all present identical screens, leaving the operator to mentally filter which information matters. State-based display switching eliminates this problem by adapting the HMI presentation to the current process state.

How State-Based Switching Works

The control system tracks the current operational state (startup, normal production, shutdown, maintenance, or emergency). When a state transition occurs, the HMI automatically adjusts several display parameters:

• Alarm suppression rules change to prevent nuisance alarms during transient states like startup (aligned with ISA-18.2 alarm management practices)
• Display priority shifts to surface the most relevant variables for the current state
• Navigation shortcuts reconfigure to provide one-click access to the most likely drill-down targets
• Trend windows adjust their time scales and variable selections automatically

During an abnormal event, a context-aware HMI can switch from the general Level 2 overview to a focused diagnostic view that highlights the affected process area, suppresses irrelevant data, and presents the specific variables needed for root-cause analysis. Research published by ISA and ABB indicates that well-designed high-performance interfaces help operators detect abnormal conditions significantly faster than traditional P&ID mimic displays, with some implementations reporting detection improvements by a factor of five or more.

Integration with ISA-18.2 Alarm Management

State-based display switching is most effective when paired with rationalized alarm management per ISA-18.2. The standard requires that every alarm has a defined purpose, priority, and required operator response. When combined with state-based suppression, operators avoid the alarm floods that frequently overwhelm control rooms during plant upsets.

State-based alarming suppresses nuisance alarms during defined transient states. For example, a low-flow alarm on a feed pump has no meaning during a planned shutdown sequence. The HMI state engine knows the plant is in shutdown mode and shelves that alarm automatically, reducing the operator’s cognitive burden during an already demanding period.

Practical Implementation Roadmap

Adopting IEC 63303 does not require replacing your SCADA platform. The standard is platform-agnostic and can be applied to any major HMI/SCADA system, including Ignition, WinCC, FactoryTalk View, or Wonderware. A practical implementation follows these phases:

1. Audit existing displays against the 4-level hierarchy model. Map each current screen to a level and identify gaps (typically, Level 1 overviews are missing entirely).
2. Develop an HMI Philosophy and Style Guide that standardizes color usage, symbols, navigation, fonts, and alarm representation for the entire facility.
3. Redesign Level 1 and Level 2 screens first to deliver the fastest improvement in operator situational awareness.
4. Implement state-based display logic by defining operational states in the control system and linking them to alarm suppression rules, display priority changes, and navigation reconfiguration.
5. Validate and train operators on the new displays using structured usability testing before going live.

Most automation vendors now provide process object libraries or ISA-101 compliant symbol toolkits that accelerate the graphical redesign work. Rockwell Automation, Yokogawa, and Inductive Automation (Ignition) all offer high-performance HMI templates aligned with these principles.

IEC 63303 vs. ISA-101: Key Differences

Engineers familiar with ISA-101 may ask what IEC 63303 adds. The core design philosophy is shared, but important distinctions exist for organizations operating across international jurisdictions.

For multinational facilities, IEC 63303 simplifies compliance by providing a single reference that satisfies international regulatory expectations without requiring parallel adherence to a US-specific ANSI standard.

FAQ

Does IEC 63303 replace ISA-101?

Not directly. IEC 63303 was derived from ISA-101 and shares its core principles. ISA-101 remains valid as a US standard. IEC 63303 provides an international equivalent with more normative language, making it more suitable for global compliance requirements. Organizations already following ISA-101 will find strong alignment with IEC 63303.

Can I apply IEC 63303 to my existing SCADA platform?

Yes. The standard is platform-agnostic. It defines design philosophy, lifecycle management, and display hierarchy principles that apply to any HMI/SCADA software, including Ignition, Siemens WinCC, Rockwell FactoryTalk View, and AVEVA System Platform.

What is the most impactful first step for IEC 63303 adoption?

Redesign your Level 1 process overview displays. Most legacy systems lack a dedicated overview screen, forcing operators to navigate between detailed screens to build a mental picture of the plant. A well-designed Level 1 screen delivers immediate improvements in situational awareness.

How does state-based display switching reduce alarm floods?

By linking alarm suppression rules to defined operational states (startup, normal, shutdown, maintenance), the HMI automatically shelves alarms that have no meaning in the current state. This prevents the cascading nuisance alarms that typically overwhelm operators during planned transitions, keeping the alarm rate within the ISA-18.2 guideline of a manageable number of alarms per operator per 10-minute period.

Ready to build operator interfaces that meet international standards? Explore our HMI templates and automation tools designed for high-performance SCADA applications.