A vehicle is not permitted to move until every door is closed and locked: the door controller collects signals from lock limit switches, photocells, obstacle sensors and drive-motor current sensing, and its decision closes or opens the “green loop” - the signal confirming that all doors are locked. The system must prevent operation with doors open above 3 km/h, close the doors automatically after the vehicle starts moving, and disengage the emergency handles above 10 km/h.
The passenger interface is strictly defined by regulations. The door-opening button illuminates green when opening is permitted; if pressed while the doors are locked, it stores the request and illuminates red. It is installed at a height of 800–1200 mm (TSI PRM: 800–1100 mm). The acoustic opening signal lasts 5 s, while the closing signal starts at least 2 s before closing. The green door button is the only permitted green light on the exterior of the vehicle. Requirements are derived from EN 14752, TSI PRM Regulation (1300/2014), TSI LOC&PAS Regulation (1302/2014), and EN 16584-1 for contrast.
Equipment used in this area includes: illuminated pushbuttons and assistance-call buttons, visual indicators and sound modules, signalling and interface relays for the door loop, protection for drive and controller circuits, door-leaf and step position sensors, and signal connectors for the door leaf and retractable step.
