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This post was last edited by yunrun on 2019-3-26 at 10:39. 1. Controller control modes: The regulator (http://yunrun.com.cn/product/list_73.html) operates in conjunction with automatic control systems. The single-loop PID controller has manual MAN, automatic AUTO, and tracking TR modes of operation, while the externally programmed regulator offers manual MAN, automatic AUTO, cascade CAS, and tracking TR modes – each accompanied by corresponding buttons that allow for seamless switching between these modes. In manual mode, the PID unit stops operating, and the operator adjusts the control output value by pressing the increase and decrease buttons on the controller panel ； In automatic mode, the internally set value defined by the operator serves as the reference value; the PID controller performs deviation control calculations according to the predetermined control logic, and this internally set value can be adjusted using the increase/decrease buttons on the controller panel ； In the cascade mode, the externally provided value from the feedback loop or other calculation modules is used as the setpoint for P1D computation ； If there is no input signal at the cascade input, it cannot be switched to cascade mode ； In tracking mode, the PID unit stops operating, and its value changes according to the quantity being tracked. 2. Seamless switching: During normal operation, the system is generally in automatic mode. During the debugging phase or when the device malfunctions, the system will automatically switch to manual mode. Due to the use of an integral control law, when the system is in manual control mode, the output value of the controller is uncertain. Therefore, when switching between automatic and manual control modes, since the output values of these two modes are different, making such a switch without taking any measures can cause significant disturbances to the system being controlled. This may lead to substantial changes in the actuator, disrupting the system’s original equilibrium state, eventually resulting in instability and even preventing the normal operation of the production process. Furthermore, this situation also occurs when switching between various control modes of the control system, as well as when disabling or activating the internal/external feedback loops in a cascade feedback system. Therefore, during the switching between automatic and manual modes, a seamless transition should be achieved. That is, at the moment of switching, the output of the regulator should remain unchanged, so that the position of the actuator does not change suddenly during the switching process, thereby avoiding any additional disturbances in the production process. This is known as disturbance-free switching. 3. Tracking: To achieve a disturbance-free switch, the PID regulator should have tracking mechanisms. That is, during automatic operation, the manual setpoint tracks the PID output, ensuring a seamless transition to manual mode. When in manual operation, the SP setpoint tracks the PV measurement value; as a result, the increment in the PID output is 0, allowing for a smooth transition from manual to automatic mode. Automatic tracking loops are incorporated in control systems composed of simulated PID regulators, so that the actuator does not change at the moment of system switching. Such hardware-based automatic tracking circuits become more complex as the complexity of the system being controlled increases, which makes their implementation difficult; in some cases, it is even impossible to achieve comprehensive tracking, thereby hindering the full utilization of PID functions. With the advent of digital regulators, the combination of microprocessing technology and artificial intelligence has enabled PID regulators to evolve in the direction of intelligence, featuring parameter self-tuning and self-correction. In intelligent regulators, the PID function can be easily implemented through software methods, and issues such as positive/negative feedback problems, integral saturation problems, limit problems, and seamless switching between manual and automatic modes can be resolved.