Electric control system for lines There are two kinds: The PLC program machine is adopted to control the whole traveling crane. And it can do all the work automatically. We adopt automatically control meters or transducer to control some parameters. This method is widely used. PC machine and PLC machine are adopted. It has all the functions above, and it is more intelligent. It can examine, record, display, and control the parameters. It also has a display and PRN device so it can show the information and output it