Shared-display BPCS function block
A hexagon containing a tag denotes a function executing in the shared-display Basic Process Control System, BPCS, the DCS or PLC that runs the regulatory loops. The bisecting line marks operator-accessible primary panel.
Read one of your own drawings.
Drop a P&ID, instrument index, or schedule. Tagsight reads it to the tag and opens a workspace you keep when you sign in.
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How it’s drawn.
A hexagon carrying the tag. The six-sided outline marks a function that runs inside the shared-display control system rather than a discrete field device. A line through the hexagon follows the same accessibility rule as a round bubble. Solid for primary and operator-facing, dashed for behind the panel. Controllers, ratio blocks, and computing functions that live in the control system take this shape.
Typical usage.
Every PID controller, ratio block, or computing function that runs inside the BPCS gets the hexagon. ISA 5.1-2022 refined the conventions for digital and shared-display devices to make this category clearer than the 2009 edition allowed.
Telling it apart.
- A hexagon is shared-display control. A plain circle is a discrete instrument. The shape tells you whether the function lives in the system or in a single device.
- A hexagon and a rounded square with a diamond are different layers. The plain hexagon is regulatory control. The diamond marks a safety function.
- The line through the hexagon still follows the accessibility rule, the same as for a round bubble.