Vertical transport saves energy
by Holger Zeltwanger, CAN in Automation (www.can-cia.org/canopen/lift)
Transportation feeds on energy. As an increasing number of people live in cities, more energy is needed for transporting them around. In the last century, the urban population has grown from 15% to 50% of the entire world population. This figure is expected to increase to 70% by the end of this century. According to research published by the United Nations, skyscrapers can lower transportation costs since less energy is used to transport people. However, high-rise buildings increase the demand on more cost-effective vertical transportation systems.
Worldwide about 7.5 million elevators are in operation. Two thirds of them are older than 20 years, and 40% have been installed before 1970. These old elevators require significant activities in modernization and refurbishment. About half of the elevators are operated in Europe; about 800,000 are in use in North America and another 800,000 are used in Japan. The increasing demand in safety and performance are further issues to be considered for future developments of elevators and escalators. To meet those requirements, including saving of power consumption and maintenance costs, control systems must become smarter and provide more diagnostic functionality and extendibility. This is only possible by using intensively networked electronic control devices.
One way to go about modernizing is to standardize the communication between control devices. This reduces wiring and also increases functionality. However, proprietary networks tie manufacturers and users to a single supplier of a control device. To overcome this, it is necessary to standardize communication interfaces. For elevator applications, the CAN in Automation international users’ and manufacturers’ group has developed the CANopen Lift application profile, also known as the CiA 417 set of specifications. The CiA 417 application profile defines interfaces for virtual devices. This allows implementing transparent gateways that interconnect physical CANopen networks or proprietary networks to another physical CANopen network. More than 200 elevators using this communication system are already in operation. They use control devices from different manufacturers.
The future is a blank sheet of paper. This means, the manufacturers and users of elevators are invited to make use of the CiA 417 network specification. They may enhance the specifications by adding new functions, including safety-related communication.
Source: CAN Newsletter Special Lift, 2005 (www.can-cia.org/newsletter/)