Relationship between the type of electro-sensitive protective equipment and the Safety Integrity Level (SIL)/Performance Level (PL)

Electro-sensitive protective equipment (ESPE) for detecting human beings often takes the form of optical sensors, such as light grids or laser scanners. These products are used for example to safeguard hazard zones on machinery. For classification of the possible risk reduction, the associated IEC 61496 product standard series defines Type 1, 2, 3 and 4 ESPE. In the past, users have equated Types 2, 3 and 4 with the Categories 2, 3 and 4 of the previous EN 954-1 standard for safety-related parts of control systems. The Categories have been replaced in the more up-to-date EN 13849-1 standard and the IEC 61508 series of control standards by the Performance Level, PL (a, b, c, d, e) and the Safety Integrity Level, SIL (1, 2, 3) respectively.

The cross-referencing of the type, Safety Integrity Level (SIL) and Performance Level (PL) in the third edition of the standard (IEC 61496-1:2012-04) is described in the article available for download.