Abstract: A circuit arrangement for indicating the status of one of a plurality of switches connected in series between signal terminals of a safety relay, each switch actuable between an open position and a closed position. The circuit arrangement includes at least one voltage sensor configured to be connected to one of the plurality of switches to provide an output signal upon sensing a presence of a voltage across the one of the plurality of switches and an indicating means associated with the voltage sensor to provide an indication signal when the voltage sensor provides an output signal. The circuit arrangement is powered by the voltage provided at one of said signal terminals of the safety relay.

Abstract: A modular safety system for controlling emergency stop applications includes a plurality of inputs, a plurality of output groups, and a plurality of safe relay outputs. The plurality of inputs is assigned to at least one of the output groups. Each output group is configured to control at least one of the plurality of safe relay outputs. The system also includes means for configuring the system and at least three freely programmable output groups.

Abstract: A modular safety system for safety control in emergency stop applications includes a base module and at least one extension module, wherein each module is arranged in a housing with a rail-mounting base, so that the modules are located in a side-by-side arrangement when mounted to the rail. The modular safety system also includes means for setting of required input and output functions, wherein the setting means is located in a side wall of the module housing, so that after mounting the modules to the rail, the setting means is covered by an adjacent module.