The purpose of the sensor is to measure the state of the controlled object and convert it into a physical quantity that can be easily processed.With the sensor, the actual state of the controlled object can be understood and compared with the instruction. The result of the comparison is processed by the controller and then used to control the action of the actuator. In this way, it can well ensure that the state of the controlled object can meet the requirements of the instruction after the automatic control system runs.
Instructions refer to the tasks that people want automatic control systems to complete. For different control systems, the forms of instructions vary.It can be an electrical signal, a handle position, a computer program, a set of data, or a combination of the above.However, in the end, it needs to be converted to physical quantities that reflect the state of the controlled object.
For the temperature control system of the temperature box, the sensor is the temperature measuring device, which is used to measure the temperature in the temperature box, and convert the measured temperature value into the corresponding electrical signal.Actuator is a temperature control device, used to control the temperature in the temperature cabinet.The controller controls the temperature control device according to predetermined rules.For this system, the instruction is the value of temperature in the temperature box that it wants to reach, and the state of the controlled object is also the value of temperature in the temperature box.