TS ISO 15519-2

TS ISO 15519-2 addresses the rules and guidance for showing measurement, control, and actuation functions in diagrams for the process industry. Its purpose is to make process signals, control loops, and actuator behavior readable in a consistent way so that engineering, operations, and maintenance teams can interpret the same diagram as a common technical language.

This standard does not stand alone for all diagramming practice. Broader topics such as diagram types, layout, graphical symbols, lines and connections, and reference designations are covered in ISO 15519-1, while rules for electrotechnical diagrams are given in IEC 61082-1. In other words, this part focuses specifically on how measurement and control elements are represented in process automation documentation.

How measurement and control elements are organised in process diagrams

GENERAL TECHNICAL CONTEXT: In process industries, measurement means detecting variables such as temperature, pressure, flow, level, or composition. Control means processing those measurements through a control strategy and using the result to influence valves, motors, actuators, or other final elements so the process stays within the desired operating state. Clear diagrammatic representation helps show which sensor feeds a loop, where the signal is handled, and how an equipment item is affected.

• Measurement chain: sensing, signal transmission, and indication
• Control chain: controller, comparison, and output action
• Actuation elements: valves, drives, and other final elements
• Connections and references: traceability and consistency across diagrams

The practical value of this part lies in providing a common representation language that reduces ambiguity when the same process function is drawn in different projects or disciplines. It supports clearer reading of control philosophy, instrumentation relationships, and equipment interactions, while the broader drawing rules remain in the related standards.