Automatic control method for before-unit roller bed of five-horizontal and three-vertical rough rolling unit

The invention provides an automatic control method for a before-unit roller bed of a five-horizontal and three-vertical rough rolling unit and belongs to the technical field of metallurgy automation control. The method includes the steps that firstly, the rough rolling unit is started, a selection switch of the before-unit roller bed is in an automatic state, when a new set message sent by the second stage is received, the before-unit roller bed begins to rotate forwards at a scale removing speed, when the head portion of a blank reaches a clamping position, the before-unit roller bed stops, abefore-unit front side guide plate is used for clamping the plate blank, whether positioning of all pieces of equipment of the rough rolling unit is completed or not is judged after clamping, if positioning is not completed, the before-unit roller bed runs at a wandering speed, after positioning is completed, the before-unit roller bed sends the plate blank to a vertical roller E1 at a feeding speed, when the head portio