Organizing HMI screens: hierarchy, navigation and faceplates
How to structure HMI screens so operators find things quickly: display hierarchy, consistent navigation, faceplates for equipment and reusable templates.
Display hierarchy
ISA-101 describes a hierarchy from overview to detail:
| Level | Content | Question it answers |
|---|---|---|
| 1 — Overview | Whole area: key KPIs, alarm summary, trends of a few critical values | Is everything normal? |
| 2 — Unit / process | A unit with its main equipment and values | What is happening in this unit? |
| 3 — Detail | One equipment group, all values, interlock status | Why is it behaving like this? |
| 4 — Diagnostics / support | Faceplates, maintenance data, help | How do I fix it? |
Navigation rules
- A fixed header/footer with area buttons, alarm banner and the current user — identical on every screen.
- At most three clicks from the overview to any equipment.
- Clicking an equipment symbol opens its faceplate; clicking an alarm opens the screen where it lives.
- "Back" and "home" always in the same place.
Faceplates
A faceplate is a pop-up for one equipment type (motor, valve, PID, analog value) built once and parameterized by instance:
- status (running, fault, mode, interlocked — with the reason);
- commands (start/stop, open/close, mode change) with confirmation for critical actions;
- values, setpoints, limits;
- tabs for maintenance (hours, starts) and diagnostics.
It matches the PLC function block of the same equipment type one to one — see motor and valve blocks.
Templates and consistency
Use screen templates, a symbol library and a style guide (fonts, colors, units, number formats). Consistency is what makes an HMI usable at 3 a.m.
Connections
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Sources
Updated 2026-10-02