Glossary · HMI, SCADA and operations
Mimic diagram
Also known as: Process display, Process graphic, Process screen
German: Prozessbild
In HMI and process control systems, a mimic diagram is a graphical display that represents a process or machine schematically, with symbols for equipment and live values and states, so operators can supervise and operate it.
- HMI and SCADA
In one sentence
A mimic diagram is an HMI display showing a process or machine schematically with live values, states and operator access.
Example
The mimic diagram of the cooling system shows the pumps, heat exchangers and valves with their states, the flow and temperature values and links to each faceplate.
How it applies
- Engineering: Current practice (ANSI/ISA-101, high-performance HMI concepts) favors muted, low-color displays in which abnormal states stand out, and a display hierarchy from overview to detail, rather than photo-realistic P&ID copies.
- Operation: Operators navigate from overview to area displays to faceplates. Consistent symbols and placement support fast orientation.
- Documentation: Operating manuals should explain the symbol set and color conventions once and show each display with numbered callouts. Keep display names and tag names identical to those in the manual and P&ID, and show values with their Engineering unit.
Mimic diagram vs. P&ID
A P&ID is an engineering document showing all equipment, piping and instruments. A mimic diagram is an operating display that shows what operators need and can simplify or reorganize the P&ID.