[PDF] Feedback Fundamentals - Caltech Computing A block diagram of a basic feedback loop is shown in Figure 5.1. The sys-tem loop is composed of two components, the process. P. and the controller. The controller has two blocks the feedback block. C. and the feedforward block. F. There are two disturbances acting on the process, the load distur-bance. d. and the measurement noise. n. The load Block diagram - Wikipedia A block diagram is a diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks. They are heavily used in engineering in hardware design, electronic design, software design, and process flow diagrams.