[. . . ] GB DESCRIPTION: The pair of photoelectric cells allows a motor to be stopped or reversed in the case of detection of an obstacle. [. . . ] GB DESCRIPTION: The pair of photoelectric cells allows a motor to be stopped or reversed in the case of detection of an obstacle. RECOMMENDATIONS: Check that your equipment has been designed to have this accessory connected to it. If the safety instructions are not strictly followed, there is a risk of serious bodily or material damage. If the indicator light does not flash (10a), adjust the alignment of the receiving cell using a wedge. MAINTENANCE: Every 6 months, check that the cells are working properly (by passing a hand in front). [. . . ] If the indicator light does not flash (10a), adjust the alignment of the receiving cell using a wedge. [. . . ]