Open And Closed Loop Systems
Open and Closed Loop Systems
Open Loop Systems
You have already been introduced to the idea of open systems in Energy Transformations. These systems have input, a process, and output, and run until a mechanical process shuts it off, or the system is shut off by the user.
A microwave, toaster, sensor door, slow-release button, or ceiling fan are examples of open systems. They are notated using simple IPO block diagrams.
Closed Loop Systems
Closed loop systems are different in that they have feedback built into the system. The system has a way to detect changes in itself and shut itself off once the set variable is met. Kettles, sensor dryers and split system airconditioners are examples of closed loop systems. A kettle has a way to detect that water has reached boiling temperature, a sensor dryer would detect humidity, and split system would have a way to detect the room temperature.
Although it seems like some systems might be closed loop, the key identifier is the system feeding data back into itself to determine when it should shut off.
For example, automatic doors at the grocery store will stay open until the doorway is clear. The doors open based on constant input of someone blocking a sensor, not the system feeding informating back in after the process.
Document sample IPO diagrams for three open loop systems, and three closed loop systems.