A cylinder stroke position measurement device for enabling common use of a rotation sensor unit in measurement of a cylinder stroke position by detecting an amount of rotation of a rotary roller by means of a rotation sensor. A motion detector monitors the copy surface to detect movement of the pages. The invention is particularly useful in program delivery systems with hundreds of channels of programming, a menu driven program selection system, and a program control information signal that carries data and identifies available program choices. The opening is covered with a sheet member except for an area where the optical axis of the optical sensor extends. A switching device applies pulses to the process control loop in response to an output from the optical sensor.