Answer: C. Operator.
Answer analysis: When discussing this question, we need to consider the basic components of an automatic control system. A typical automatic control system usually includes several key parts for realizing automatic monitoring, regulation and control of the system. Now, let's analyze each option one by one:
A. Detection element: This is an important component of the automatic control system. It is responsible for detecting the actual state of the controlled object (such as temperature, pressure, flow, etc.) and converting these states into signals that can be further processed. The detection element is the basis of the feedback control mechanism, so it is an essential part of the control system.
B. Regulator: In an automatic control system, the regulator (sometimes also called a controller) is the core component. It receives signals from the detection element and calculates the control signal according to the preset control algorithm, and then sends it to the actuator. The regulator is responsible for adjusting the control signal according to the system state to achieve stable control of the system.
C. Operator: Although operators play an important role in the operation and maintenance of the automation system, they are not an inherent part of the automatic control system. The operator is mainly responsible for monitoring the operating status of the system, making necessary interventions (when the automatic control system cannot handle certain abnormal situations), and performing system maintenance and troubleshooting. However, from the perspective of the automatic control system, the operator is not part of the automatic adjustment and control functions within it.
D. Transmitter: In some cases, the detection element and the transmitter may be regarded as two separate parts, but in many systems, their functions are closely related. The transmitter is usually responsible for converting the signal output by the detection element (which may be weak or non-standard) into a standard signal that the controller can accept. Although in some systems, the functions of the detection element and the transmitter may be integrated together, the transmitter, as a component that converts the detection signal into a standard control signal, is an important part of the automatic control system.
In summary, C. Operators are not part of the automatic control system. Although they are essential to the operation of the automation system, they do not constitute a part of the automatic adjustment and control functions within the automatic control system.