KonnectSymbols
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Quick reference

HMI, SCADA, and P&ID glossary

Plain-language definitions for common industrial automation, display-design, and documentation terms.
Reading time
6 min
Reviewed
2026-08-09
Affected packs
All live packs

Core terms

TermWorking definition
HMIHuman-machine interface: the display and interaction layer used to observe and operate a system.
SCADASupervisory control and data acquisition: a system for monitoring and supervisory control, often across distributed assets.
P&IDPiping and instrumentation diagram: engineering documentation of process equipment, piping, instrumentation, and functional relationships.
PLCProgrammable logic controller: an industrial controller that executes control logic and interfaces with field equipment.
DCSDistributed control system: an integrated control architecture commonly used in continuous and batch processes.
TagA project-defined identifier for equipment, instrumentation, or a control function.
FaceplateA reusable operating panel for commands, modes, status, alarms, and related navigation.
PermissiveA condition that must be satisfied before an operation is allowed.
InterlockLogic that prevents or changes operation to protect people, equipment, or process conditions.
Bad qualityAn indication that a displayed value or state cannot be trusted as a current valid measurement.
SpritesheetA single raster image containing multiple consistently sized frames for indexed display.
Visual languageA coordinated set of geometry, typography, color, state, and interaction rules.

Sources and boundaries

KonnectSymbols is independently developed and is not endorsed by ISA, IEC, or ISO. These educational notes do not reproduce or replace current standards, project specifications, regulations, or an approved project legend.