Emergency stop pushbuttons: choice of actuators and contacts

For increased safety, Wieland's SNH series incorporates an innovative contact block drop-off feature that triggers a signal output should the contact block become dislodged due to vibration or physical damage. There is an additional normally-open contact pre-installed in series with the main contacts; this NO contact opens as soon as the contact block becomes detached, thereby enabling the safety-related control system to put the machine into a safe state. Wieland says that an illuminated stop button also provides enhanced safety for machine users.

SNH pushbuttons are unlatched by twisting the knob or by means of a key and are supplied with or without a protective collar. The pushbuttons are rated to IP69 and the switching capability of the contacts is 250V/16A AC. They have been designed for use in conjunction with the company's 400 series relays, SMA safety sensors and samos PRO, a compact modular safety controller for machine and automation control (see this article: samos PRO modular safety controller is more economical).

Follow the link for more information about Wieland's safety technology or contact Wieland Electric Ltd for details of the SNH series emergency stop pushbuttons.