The invention relates to a control system for electrically controlled installations. The control system comprises at least one portable, mobile manual operator-control instrument for display of information and for input of control commands by an operator-control person. The manual operator-control instrument is provided with at least one manually actuatable safety switching element, with which safety element an illuminating device is associated. The control system comprises an illumination control device, which is designed for electrically and/or electronically controlled adaptation of a visually perceptible luminous intensity of the illuminating device.