A method and a device for securely switching between operating modes of an industrial controller for machine tools or production machines are described. Before the operating mode is switched, the operator is identified by identification means that transmit to an operator's console of the controller a redundant binary enable signal after a successful identification. The operator is allowed to switch between operating modes by using the keys of the operator's console implemented in safe technology as long as the enable signal is received and is error-free. With the method and the device, the operating modes of an industrial controller for machine tools or production machines can be easily, reliably and cost-effectively switched.