Sensors suit safety applications

Last year there was only one, but now there is a whole family of inductive sensors from IFM Electronic that are safe to use in a Category 4 (EN954-1) or SIL 3 (EN61508) situation.

Last year there was only one, but now there is a whole family of inductive sensors from IFM Electronic that are safe to use in a Category 4 (EN954-1) or SIL 3 (EN61508) situation.

As many customers have already found, no longer is there any need to rely on mechanical devices alone in a safety application.

The range now covers rectangular (40x40) types both flush and nonflush, M30 and M18 devices.

The M30 is even available in a version for safe use in hazardous areas (safety Cat 3 and ATEX 3D/3G).

The Cat 4 M30 is designed with food washdown environments in mind, being constructed of stainless steel and Peek, with an IP rating of 69K.

The stainless steel M18 is also rated to IP69K.

All fail-safe inductive switches from IFM Electronic are constructed with full redundant and diverse internal circuits, certified by the TUV Rhineland, but otherwise has all the advantages of an inductive sensor: with no moving parts, IP67, standard M12 connector etc.

Now, readers may think an inductive sensor which needs no special target would be easy to defeat - but that would defeat the object of safety.

The target may be nothing special, but its position in the right place at the right time is what counts.

When the target is present, any other piece of metal between the switch and the target will cause the output to switch off.

Setting the unit is not difficult either, because the LED helps in adjustment, while incorporating a delay to befuddle the fiddlers.

To operate, the fail-safe switch from IFM Electronic is connected to an external controller with safe outputs, though it could equally be connected to a safety plc running approved software, and IFM Electronic also offer a safety slave for AS-interface Safety at Work with the controller built in, capable of monitoring eight fail-safe inductive switches simultaneously.

Functional safety is assured with the IFM Electronic fail-safe inductive system; coil damage, component health, cross-monitoring, short-circuit protection - all aspects are continuously checked by a test pulse from the controller or PLC.

Any fault, at any time is instantly signalled.

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