LE-BS series differential line is a kind of special aluminium profile or special steel structure guide. It is equipped with plastic-steel composite roller double-speed chain to form conveying equipment. The pallet is placed on double-speed chain, and the conveyed goods are placed on pallet or enlarged pallet by supporting device. The tray's running speed is an integral multiple of the chain's running speed. Series of equipment can adjust the line structure according to the operation content and production rhythm, combined with the production process, adopt two-level computer distributed control method, plus unit operation panel, fault detection warning system, make the whole control system more perfect.