1. Project Name: Qingdao Metro Line 4 BAS Monitoring System
2. Country / region: Qingdao, China
3. Industry: Rail transit
4. Number of I/O signals: 800 points per station, the total number of points is greater than 15000 points.

5. CPU model: CPU402-0701

Parameters: High-performance redundant CPU, with 2 Ethernet interfaces, 1 redundant port, program space 32M, support Ethernet remote I/O.

6. Technical Description:

BAS field-level monitoring system mainly includes redundant PLC controller, input output (I/O) modules, various types of sensors, actuators and field control networks. BAS system field control network adopts optical fiber ring network structure, by the BAS industrial switch to form an optical fiber ring network, redundant PLC, RI/O, touch screen and other equipment in the station are connected to this ring network.

A set of redundant NA400 series CPU402-0701 controllers is installed at one end nearby the vehicle control room. According to the setting of the electromechanical equipment, the RI/O of the NA2000 series is configured on site, and the RI/O is accessed through the optical fiber ring network, and monitors and manages the electromechanical equipment (HVAC, escalator, lighting, water supply and drainage equipment) at both ends of the station. A set of NA2150-21 panel of Atekon Technology was installed in the PLC control cabinet of the BAS system for field-level operation. The panel uses 15.6-inch touch industrial control integrated machine. It’s convenient for on-site maintenance personnel to monitor the status of on-site electromechanical equipment and operation instructions through the HMI interface so as to achieve maintenance management of BAS equipment. The panel is connected with BAS system switch.

Using NA2000 series small PLC CPU2001-2402 as serial communication conversion equipment, the small PLC has two integrated independent RS485 interfaces, to achieve data exchange between remote water meters, electric insulation, air conditioning water systems, EPS, water supply and drainage systems. At the same time, two sets of CPU2001-2402 are set up in the IBP of the vehicle control room, which form a redundant communication channel with FAS, receive and process fire information from FAS, and start responsive abnormal working condition mode.

BAS system and integrated monitoring system achieve data transmission through the CMM402-0105 Ethernet module. If hot standby switch occurred between the main and standby controller, the Ethernet modules on the same slot will be switched accordingly too, and provide a unified IP address (the IP addresses will exchange automatically after switching). When the communication between the main controller and the integrated monitoring or the optical fiber ring network is interrupted, the system will automatically switch to the standby machine, at which time the standby machine takes over the entire system and becomes the current host to ensure the normal operation of the system. The system architecture is shown in the following figure (schematic diagram):