Closed loop control principle: Optional single, double or multiple columns
　operation, PLC real time control for high accuracy ;

Human engineering: each column is equipped with control system,
　applies to six, eight or more columns; This set is composed of 1 master
　column and 3 slave columns; each column is equipped with hydraulic
　power unit.;

Safety precautions: mechanical and hydraulic double locking function
　when loading, overload protection; up/down limit switc

Failure self diagnosis function: when seriously asynchronous or column
　power failure, the lift stops immediately.