CANopen in underground door system
Source: CAN Newsletter, December 2005
We often come across automatic doors in our daily lives. For the most part, we only notice them when they do not work. The Swiss door manufacturer Kaba Gilgen together with the automation specialists at Bircher have given this special attention so that the enormous flow of people using the underground railroad in Hong Kong and Kaohsiung/Taiwan would not be backed up.
An increasing number of underground railroad platforms are separated from the track system by automatic doors. This provides additional safety and comfort and also saves a considerable amount of energy, especially in countries where the underground railroad systems are air conditioned because of the high temperatures. This is the case in Hong Kong and Kaohsiung, Taiwan. Day in and day out, the doors open automatically after the train arrives and close before it departs. If one of these doors fails, it can considerably influence safety for the passengers and also affect the total operation of the underground railroad system. If, as in Hong Kong, you are talking about 74 platforms with 40 doors each, it quickly becomes clear that only careful maintenance and diagnostics can guarantee the functionality of the door system over the long lifespan of up to 35 years. Therefore, it was decided that the individual door systems would be networked and monitored centrally. Each individual door has a DCU (Door Control Unit), which controls the motors and closing mechanisms based on commands received. These units make sure that the forces and speeds for the doors remain within safe limits. They also monitor the status of the sensors and actuators on the doors and continually send data to the PSC (Platform Screen Door Controller). Each row of doors on a platform is monitored by a PSC and a PLC. The DCU and PLC are networked via CAN. The transfer speed of 100 Kbit/s is sufficient for the timing requirements, and the CAN network can also be used for the 180-m platforms in this speed range. The PSC is the central unit that collects data from the doors and transfers it to the SMS (Station Management System).
