Schmersal Pull Cord Switch, Model Number: Zq 900

Application:Pull-wire Emergency Stop switches are mounted on machines and sections of plants which cannot be protected by guards. In contrast to mushroom head Emergency Stop push buttons, on pull-wire switches, the Emergency Stop command can be initiated from any point on the wire.In combination with one of the AES and AZR range safety monitoring modules pull-wire Emergency Stop switches can be used for Control Category 3 or 4 to EN ISO 13849-1.Design and mode of operation:All of the pull-wire Emergency Stop switches conform to European Standard EN ISO 13850. They have a positive linkage between the NC contacts and the wire rope. The pull-wire emergency stop switches are brought into the operational condition by pre-tensioning the wire, i.e. the NC contacts are then closed and the NO contacts open.All of the pull-wire Emergency Stop switches have wire-breakage monitoring. On pulling or breakage of the wire, the NC contacts are positively opened and the NO contacts are closed. The pull-wire Emergency Stop switch can then only be returned to the operational condition by a resetting operation.