New design safety interlock

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NHP and Schmersal recently introduced an innovative new switch, the MZM 100, a safety interlock with a non-mechanical operating principle, which means it doesn’t need an actuator key.

The MZM 100 is a magnetic interlock, whereby it uses a powerful electromagnet to lock the machine guard. The switch also detects and monitors the actuator plate through an integrated non-contact sensor that uses Schmersal’s patented pulse-echo technology.

The unique combination of the magnetic operating principle and the pulse-echo sensing offers multiple advantages. The switch is not subject to mechanical wear as there are no moving parts; the non-contact sensor tolerates larger door misalignments; and, the pulse echo technology allows a single safety controller to monitor multiple units, up to 31 in series, and, not only other MZM 100’s, but other pulse-echo units such as the AZM 200 interlock and the CSS 180 and CSS 34 safety sensors, without detriment to the safety level.

Even without a positive-linked mechanical locking mechanism, the MZM 100 fulfils the requirements of Control Category 4 (EN 954-1) or SIL 3 (IEC 61508). The magnetic locking principle complies with EN 60947-5-1.

The MZM 100 also has an IP 67 protection class rating, making it suitable for the food-processing industry or wherever high hygienic standards need to be maintained.

For further information on the MZM 100 please contact your local NHP representative or visit