HMI

How it is used

Said letter by letter: H-M-I. Automation engineers design HMI screens, link them to PLC tags and set up user levels. Operators talk about what the HMI shows: 'the HMI says door open'. On larger sites, many HMI functions are combined in a SCADA system.

Example sentences

1. Add a button on the HMI so operators can send the robot home.

2. The HMI shows the alarm, but it doesn't tell you which sensor caused it.

Common collocations

• HMI screen
• HMI panel
• design an HMI
• on the HMI
• HMI alarm page

Related terms

• PLCShort for programmable logic controller: a rugged industrial computer that reads inputs from sensors and switches, runs a control program and drives outputs such as motors, valves and lamps.
• SCADAShort for supervisory control and data acquisition: software that collects data from PLCs and devices across a plant, shows it on screens and lets operators monitor and control the process.
• alarmA message, light or sound from a control system that tells the operator something is wrong or needs attention, often with a number and a short text.
• tagA named variable in a PLC, HMI or SCADA system that holds a value such as an input, a setpoint or a motor status, for example Conveyor1_Running.
• home positionA safe, known starting position that a robot or machine returns to before starting a cycle, after a stop or before being switched off.

More terms: PLCs and Industrial Control

• I/O
• ladder logic
• relay
• analog signal
• scan cycle
• function block
• structured text