An agricultural implement has a depth control system in which a position sensor directly measures linear translation of a hydraulic cylinder that lifts and lowers a work unit on an implement frame to set and adjust the depth of the work unit without the use of a rockshaft. The position sensor may be positioned adjacent to or integrally formed with the hydraulic cylinder, and provides a voltage to a controller remote from the implement. The controller automatically adjusts the flow of hydraulic fluid to and from the hydraulic cylinder to maintain the depth of each work unit at an operator-selected level and can be used to calibrate the actual position of multiple work units relative to the frame and to one another.
