Easy switching from PNOZ Classic to PNOZsigma safety relays

17 October 2007

Pilz Automation Ltdvisit website


Easy switching from PNOZ Classic to PNOZsigma safety relaysPilz PNOZ Classic safety relays were the first such products on the market in 1987 and were quickly adopted by many companies as an in-house standard. However, Pilz has since developed the PNOZ X range, the PNOZelog range and, most recently, the slimline and multifunctional PNOZsigma range. With the advance in technology and increasing difficulty in sourcing components, Pilz will discontinue the Classic range from 1 February 2009.

There has already been an announcement about replacements for the PNOZ 1 and PNOZ V Classic relays and now Pilz is publishing a document to help customers migrate from Classic relays to PNOZsigma relays. The first section is a straightforward 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 to deliver the same functionality as the Classic relay, the expansion module options are also identified. Interestingly, a quick look at this section highlights the way a small number of PNOZsigma relays are replacing a very wide range of Classic relays, which will significantly simplify ordering and stockholding for customers.

By far the bulk of the publication is devoted to application examples. These show how the Sigma relays need to be connected in order to replicate the functions performed by the Classic relays. Terminal designations are clearly shown, so users can easily see how to modify their wiring schematics and, in the event of having to replace a relay in an existing control system, rewire the relay itself.

If relays are swapped on a 'like for like' basis during machine repairs, installers should ensure that they comply with the sections of PUWER (Provision and Use of Work Equipment Regulations) relating to control systems. Note that any physical changes to control systems MUST be properly documented.

If further advice or assistance is required, UK customers can contact the technical support team at Pilz by email , telephone 01536 460766 or fax 01536 460866. Outside office hours, technical support is available by calling 01536 462203.

Please contact Pilz to request a copy of the PNOZclassic-to-PNOZsigma checklist, or visit and enter webcode 0994 for more information about PNOZsigma safety relays.

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