DASYLab is a PC program that allows a data acquisition and control application to be represented as a data flow diagram directly on the screen.

Icons selected from a module bar are positioned and connected with the mouse to form a schematic flowchart of the different stages in the flow of data -- input, processing, and output -- with a module represented by an icon at each stage. This schematic flowchart is called a worksheet.

A physical worksheet can be up to 2000 by 2000 pixels. When it is larger than the monitor screen, it can be scrolled horizontally and vertically. Editing the worksheet is easy, and modules can be added, moved, and deleted with a click of the mouse.

A worksheet contains up to 256 modules, but conceptually a worksheet can be any size. A worksheet can be represented as a custom icon and placed in another worksheet. These custom icons can be stored by name as a library to be used in many applications.