Colour-coded warnings

Siemens Automation and Drives (A&D) has added new diagnostic functions to its Sipart PS2 electropneumatic positioner.

The positioner signals imminent malfunctions in the valve or actuator using “traffic light signalling” in accordance with the Namur NA64 and proposed NE107 requirements. Siemens says that by detecting the early stages of a serious fault, maintenance schedules can be optimised to support both production and safety requirements.

The Sipart PS2 positioner communicates the fault condition using a green wrench for "Maintenance required", a yellow wrench for "Urgent maintenance request", and a red wrench for "Failure of the valve or actuator, or failure about to occur".

This three-step message hierarchy provides details on the valve or actuator to include: blocking of a pipe, progressive increases in friction, wear of a valve plug or seat, incipient diaphragm tears in the actuator and other potentially dangerous conditions.

An innovation of the Sipart PS2 Auto-Tune software is that it automatically learns the reference performance characteristics of a new valve and actuator system. This process provides a performance benchmark stored in the positioner memory and is said to eliminate the requirement to define actuator models and other installation details through complex calculations, table evaluations and measurement procedures.