An innovative position switch for protective doors from the Siemens Industry Automation Division has a number of practical advantages.

In addition to fulfilling the ASIsafe standard, the SIRIUS 3SF1324 position switch also fulfills the stringent demands of safety category SIL 2 / PL d and is equipped with a special logic: the operator receives a checkback signal from the magnet and no longer has to open the protective doors each time after magnet release in order to set machinery or plant to safe state again.

This feature facilitates faster restart after door release. The new position switch with tumbler and ASIsafe is available in three versions: with auxiliary release at the front, with escape release at the front as well as with both auxiliary release at the front and escape release at the rear. The Sirius 3SF1324 position switch is especially advantageous for safety door tumblers connected in series or when several protective doors are to be controlled as a group. It is no longer necessary to open and close each door individually in order to establish the safe state. This both reduces downtimes and ensures that the machine or plant resumes operation much quicker.

The engineers at Siemens have developed a special logic for the new position switches: the double evaluation of the actuator required for safety category SIL 2 / PL d now takes place within the switch. This information is then reported safely to the control system via one of the two ASIsafe transmission channels, while the second channel is simultaneously used for the operating status signals or status query of the door interlock magnets.

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electrical industry machinery safety news, e-lec.org