Valve positioner

ISA 5.1-2009/2022 (final control element actuators) / PIP PIC001

Drawn as

A control valve with a small box on the stem below the dome (the positioner), joined to the stem, with a signal line entering the box.

Meaning

Positioner on a control valve: compares the controller signal with stem position and drives the actuator. An accessory of the control valve; it is not modelled separately.

Variants

Smart (HART/fieldbus) positioners may be shown as a bubble with ZC or as a box with "P"
Many P&IDs omit the positioner and show it only in the instrument index