Flow Charts

definition- a schematic representation of a system or process and indicates at which stage quality control should be taken. it is a visual rather than text based form of communication which provides an easy reference for the viewer

Open Loop

• Has no feedback on quality of each stage of production
• Process will continue without any interference from control system even with output change
• is a disadvantage as it can't detect or correct errors in the process
• used in simple processes where feedback isn't vital, and is low cost. example is light switch

Closed Loop

• Utilises feedback to make decisions about changes to a process e.g. quality control
• most of them are automatic e.g. temperature controllers on air conditioning systems
• Can detect errors early in production and rectifies them
• An example is fitting a dimmer switch to the light switch above, the system gives feedback and light can be dimmed.