Towable Passenger Stair installed electrical line mainly includes lighting system, control system and height display instrument and other three parts.
1. Lighting system
The lighting system consists of flat table lamps, ladder lights and warning lights. The control of the lighting system is transferred by the electrical box, wiring bar and sent to the flat table lamp, ladder light and warning light.
2. Control system
The control system is composed of height display instrument, control circuit and electrical control relay.
a, height display instrument
The height meter adopts the single chip microcomputer as the core, and samples the signal through the proximity switch on the guide pole, and sends the signal to the display machine for calculation, showing the instantaneous value of the ladder movement (that is, the actual height of the ladder). Due to the use of advanced computing technology and high-quality sampling devices, the display is highly accurate and the response is fast and sensitive. At the same time, because of the use of non-contact induction switch, the device is not easy to damage. In addition, the host is equipped with computer memory chips, measurement data can be maintained in long-term memory. The height meter is also equipped with a microcomputer reset button, which can be used for reference calibration. In case of interference and other reasons, the display error occurs, you can lower the ladder to the lowest height, and press the reset button to calibrate.
In addition to showing the instantaneous height of the platform lifting, the height display instrument also shows the change of the number of teeth of the indicating rack, reflecting the analog indication of the rise and fall and the support signal as well as the buzzer signal when the ladder body is falling.
b, activity platform control circuit
There are two sets of operating expansion platform and fine-tuning switch. One set is located on the cab operation control panel, which can be operated by the driver; The other set is at the front end of the right guard plate of the platform for on-site operation by the staff and intuitive docking of the aircraft.
c, ladder lifting lock position control circuit
When the boarding ladder is raised to a certain height, the guide post teeth are locked by a lock block to make it stiffly connected. When the height needs to fall, the electric switch controller automatically completes the signal recognition and opens the lock block, and the ladder body drops.
3, safety collision protection system
The left and right ends of the buffer rubber tube at the front end of the platform are installed with proximity switches and 300mm distance alarm photoelectric system. Once near the aircraft or obstacles, it can automatically alarm and automatically cut off the platform expansion control circuit to avoid platform collision with the aircraft.