Industrial Engineer · phase 7 of 16
HMI
Human-Machine Interface used by operators to view status, enter commands, acknowledge alarms, and adjust setpoints.
The Explain card
- Plain English
- The HMI is the screen the operator uses to run the machine. It shows status, takes commands, displays alarms and lets setpoints be changed, all by reading and writing PLC tags.
- Example
- A panel mounted touchscreen shows the line running, a jam alarm on conveyor 3, and a button to reset it. Every one of those is a tag in the controller behind it.
- Why it matters
- The HMI is where the design of the machine meets a human at two in the morning, so a confusing screen is a slow recovery and a dangerous one. It is also a second writer to the controller's tags, and a button that writes to the same tag the logic writes is a fight the operator loses.
- Hook
- The machine's face.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During commissioning, the technician checks the HMI motor-current trend while ramping the conveyor drive from 10 to 60 Hz.
Letter by letter
- H Human identifies the person-side of the interaction
- M Machine identifies the equipment-side of the interaction
- I Interface names the shared point of interaction
Where it came from
- Origin
- English initialism formed from human-machine interface
- Entered the language
- 1980s
- What changed
- The wording increasingly displaced man-machine interface and became standard in industrial automation.
How it is spelled
- Capitalisation
- Written HMI in uppercase, including mid-sentence
- Plural and possessive
- Plural HMIs; singular possessive HMI's; plural possessive HMIs'
- Out loud
- Spelled out letter by letter.
Same family
- PLC
- VFD
- RTU
- DCS
Broken into chunks
-
HMI
- HCI
- MMI
- OIT
Where it sits in the deck
Phase 7: PLC Related Automation Systems
The neighbours a PLC lives beside on a plant floor, from operator panels and SCADA up to the motion and batch systems it hands work to.
