Subway Screen Door System Based on CAN Bus
The subway screen door system based on CAN bus means that PSC (Platform Isolation Door Controller), PSA (remote operation alarm panel) and each DCU (door controller) in the system are a network node connected to the CAN bus. , CAN bus distributed structure can ensure that the failure of any node on the network will not affect the normal operation of other nodes in the entire network, and can control the screen door throughout the network, modify operating parameters, sound and light alarms and other functions through the network. The screen door control system should also use hard wire transmission on some important nodes and commands, making full use of its high reliability and anti-interference performance to ensure the reliability of the entire control system. Like the PSC and the signal system, between the PSC and the PSL (station end control box), as well as the transmission and feedback of the opening and closing commands of the screen door, hard wire transmission is required. Examples are as follows:
A subway line has 74 platforms, each platform has 40 doors, and each door has a DCU (door controller), which controls the motor and closing mechanism according to the instructions received. They include monitoring the status of sensors and actuators on the door, and continuously transmit the data to the PSC (Platform Isolation Door Controller).
Each column of doors on the platform is controlled and monitored by PSC and B&R 2003. DCU and PCC are networked through CAN bus, and the transmission speed is 100KBits. This is sufficient for timing requirements. The CAN bus can transmit at the same speed within the range of a station with a maximum length of 180 meters. PSC collects data from the door and transmits it to SMS (Station Management System). In addition, a PP120 from the B&R Power Panel series is used in the control room, where important information such as doors and their functions are displayed, and time reports are transmitted to the local environmental monitoring system for further analysis.
In addition to the DCU connection via the CAN bus, the PSC communicates with the LESS (Local Environmental Monitoring System) via RS485. Communicates with PTE via RS232, and communicates with the display via Ethernet. Communicate with PTI through switch signal. The communication flexibility offered by B&R 2003 undoubtedly meets these network requirements. The CP476 CPU handles all door controllers, digital I/O and network connections.
