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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 502

Human-Machine Interface (HMI)

What is Human-Machine Interface (HMI)?

Human-Machine Interface (HMI)Software or panel that lets operators visualize process state and issue commands to PLCs, DCS, and SCADA systems.


A Human-Machine Interface (HMI) is the graphical layer that bridges operators and the industrial process, showing live tags, alarms, trends, and mimic diagrams while allowing operators to start, stop, or adjust set-points. HMIs run on dedicated panels next to machinery or as control-room workstations connected to SCADA or DCS servers. Because HMIs can write to PLCs and frequently run aging Windows builds with weak credentials and exposed services (VNC, RDP, web), they are prime initial-access targets in OT incidents. Hardening typically involves removing dual-homed network adapters, role-based access control, strong authentication, application allow-listing, and continuous monitoring.

Examples

  1. 01

    A touchscreen HMI on the factory floor showing tank levels and start/stop buttons for pumps.

  2. 02

    A control-room WinCC or Wonderware screen with mimic diagrams of an entire production line.

Frequently asked questions

What is Human-Machine Interface (HMI)?

Software or panel that lets operators visualize process state and issue commands to PLCs, DCS, and SCADA systems. It belongs to the OT / ICS / IoT category of cybersecurity.

What does Human-Machine Interface (HMI) mean?

Software or panel that lets operators visualize process state and issue commands to PLCs, DCS, and SCADA systems.

How does Human-Machine Interface (HMI) work?

A Human-Machine Interface (HMI) is the graphical layer that bridges operators and the industrial process, showing live tags, alarms, trends, and mimic diagrams while allowing operators to start, stop, or adjust set-points. HMIs run on dedicated panels next to machinery or as control-room workstations connected to SCADA or DCS servers. Because HMIs can write to PLCs and frequently run aging Windows builds with weak credentials and exposed services (VNC, RDP, web), they are prime initial-access targets in OT incidents. Hardening typically involves removing dual-homed network adapters, role-based access control, strong authentication, application allow-listing, and continuous monitoring.

How do you defend against Human-Machine Interface (HMI)?

Defences for Human-Machine Interface (HMI) typically combine technical controls and operational practices, as detailed in the full definition above.

What are other names for Human-Machine Interface (HMI)?

Common alternative names include: HMI, Operator interface, Operator panel.

Related terms