From Classic to modern relays
November 1st 2007

Pilz PNOZ Classic safety relays are used by many companies as an inhouse standard. However, Pilz has since developed the PNOZ X range, the PNOZelog range and, most recently, the slimline, multifunctional PNOZsigma range. With the advance in technology and increasing difficulty in sourcing components, the company will discontinue the Classic range from 1 February 2009.

A document is available to help customers migrate from Classic relays to PNOZsigma relays. The first section is a checklist of PNOZclassic relays and their supply voltages to enable users to identify which PNOZsigma relays to use as replacements. If an additional PNOZsigma expansion module is required, expansion module options are also identified.

The bulk of the publication is devoted to application examples.

These show how Sigma relays need to be connected in order to replicate the functions performed by the Classic relays. Terminal designations are clearly shown. If relays are swapped on a 'like for like' basis during machine repairs, installers should ensure that they comply with the sections of PUWER relating to control systems.

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