Schneider / Preventa and Harmony XPS safety

The same safety module can achieve PL e Category 4, or PL d Category 3, or Category 1, depending entirely on how it is wired and what is connected to it. The rating belongs to the application, not the part.

Preventa, now also branded Harmony XPS, is the Schneider machine safety range. Safety relay modules for emergency stops, guards, light curtains and safety mats.

A safety relay does not have a fixed safety level

The most misunderstood thing in this range, and Schneider states it plainly in its own documentation.

Across different application diagrams for the same XPSUAF module, Schneider notes:

Same module. Three different achieved levels.

The qualifier Schneider uses every time is with appropriated input and output devices. A single channel emergency stop into a PL e capable module does not give you PL e. The whole chain determines the level: the input device, the wiring, the module and the output devices.

What that means practically

Buying a module rated PL e Category 4 does not make a circuit PL e Category 4. If someone has specified a level, the wiring configuration is part of that specification.

And in reverse: if you rewire an existing circuit from two channel to one channel, you have changed the achieved level even though the hardware is unchanged.

We supply the part you specify. The safety level achieved by your installation belongs with whoever holds the machine's safety assessment, and this is exactly why.

XPSAF has been replaced by XPSUAF

Schneider publishes a direct migration between the two, so this is the current answer for a failed XPSAF.

It is not a drop-in. The terminals and the configuration method differ, and Schneider's migration document exists precisely because the wiring needs checking.

Or keep the original. A surplus or tested used XPSAF of the same reference goes back into the existing wiring unchanged, which on a machine with a documented safety assessment is often the better answer. Changing the module means revisiting the assessment.

Tell us which you want and we will quote both.

The XPSU ranges

Two modules for two functions

Schneider notes that with two XPSUAF modules, two similar or different safety input devices can be handled, with 3 NO safety outputs for each function.

And where a machine needs both a safety mat and another function, Schneider specifies a combination of XPSUAK plus XPSUAF.

One module generally handles one safety function. If a machine has an emergency stop, a guard interlock and a mat, that is not one module however many contacts it has.

The extension module caveat

Important and easy to miss.

An XPSUS with an XPSUEP14AP extension goes from 2 NO safety outputs to 6 NO.

But Schneider is explicit: all those safety output contacts can be used for just one function.

So the extension gives you more contacts for the same function, not more functions. If you need to stop three separate things independently, six contacts on one module does not do it.

The extension connects via the EXT side connector.

The module is configured, not just wired

This is why a replacement does not simply drop in.

The XPSUAF has selector positions that set its behaviour:

And the start configuration changes which terminal you wire to. Schneider's example: START configuration position 3 uses the S34 terminal, while position 1 uses the S39 terminal.

So a replacement module arrives at default settings, and the existing wiring assumes a particular configuration. Fit it without setting the selectors and either it will not start or it will not perform the intended function.

Photograph the selector positions before removing the old module. Same advice as the ABB CM relays on our monitoring relay page, and for the same reason.

Published configuration numbers

Schneider numbers the application configurations. Examples from the documentation:

If your documentation refers to a configuration number, that is what it means. It identifies both the wiring diagram and the selector setting.

The B2 terminal and a common earth reference

A wiring requirement that causes intermittent faults when it is missed.

Schneider specifies B2 as the terminal for common reference potential for 24 V DC signals, and states that the power supply of the connected equipment must have a common reference potential connected to this terminal.

So if the safety module and the connected devices run from different power supplies, those supplies need a common reference. Without it the signals have no shared zero, and the behaviour becomes unreliable rather than obviously broken.

Worth checking on a panel where a safety circuit misbehaves intermittently and the wiring all looks correct.

XPSAF5130, the common one

Still very widely installed in New Zealand.

The 24 V AC or DC dual supply is worth noting. The same module suits either, which is unusual and useful when a panel has one and not the other.

Published contact current ratings for this module vary between sources. If the contact rating matters for your load, tell us and we will confirm it against the Schneider datasheet rather than a listing.

The Preventa families

Relay module or safety controller?

The same decision as PNOZ against PNOZmulti on our Pilz page.

A relay module does one function and is set with selectors. Simple, no software, and a replacement is configured in minutes.

A safety controller does many functions and is programmed. Cheaper per function once you have several, and a replacement arrives blank and needs the configuration file.

If you run XPSMC controllers, confirm the configuration files are backed up. That is the part that is not replaceable off a shelf.

Preventa and Harmony XPS

Both names are in use. Schneider now lists these modules under Harmony XPS branding, and they are the same products as the Preventa range.

Same situation as TeSys D and TeSys Deca on our contactor page. If a drawing says Preventa and a current catalogue says Harmony XPS, that is a rename.

What to send us

The full reference off the module.

The selector positions, if the module is configurable. A photo of the front captures them.

What the module is monitoring. Emergency stop, guard, mat, light curtain.

Whether it is single or two channel.

Whether an extension module is fitted.

Whether you want a like-for-like or the current replacement, because on a machine with a documented assessment those are different decisions.

Important: safety replacements

Safety components are certified as part of a machine's safety function, with a rated Category, Performance Level or SIL.

A like-for-like replacement of the same reference preserves the existing assessment. A substitution may not, and on this range the wiring configuration matters as much as the part.

We will supply the exact part you specify. If you ask for an alternative we will tell you what we believe is equivalent and what differs, but the decision belongs with whoever is responsible for the machine's safety. We are a parts supplier, not your safety engineer.

What we can supply

Current production. XPSUAF, XPSUS, XPSUAK, XPSUEP extension modules and XPSMC safety controllers, plus safety switches, light curtains and mats. Quoted with a delivered lead time.

Superseded. XPSAF, XPSAFL, XPSAC and earlier Preventa modules. Surplus and tested used, which keeps an existing safety circuit exactly as assessed.

We buy Preventa

Safety modules hold value, and the superseded XPSAF range is worth real money to plants that would otherwise have to rewire and reassess. If you are decommissioning, do not scrap them. See Sell To Us.

Related

Schneider overview. Harmony control and signalling, including trigger action emergency stop heads.

For safety from other brands see Pilz PNOZ, ABB Jokab, Omron G9SA and Allen-Bradley Guardmaster.

Send us your references

Include a photo of the selector positions if the module has them, because that is what a replacement needs set. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with Schneider Electric. Schneider Electric, Preventa and Harmony are trademarks of Schneider Electric. All trademarks, brand names and references are the property of their respective owners and are used here for identification purposes only. Information on this page is for identification and does not constitute a safety assessment.