Electric control signal for regulating valve

Voltage (0–10V) and current (4–20mA) belong to continuously controlled valves. The opening degree of this valve is proportional to the magnitude of the signal value ； Voltage or current signals – it’s just a difference in signal format. Essentially, they are all commands for the valve opening degree (the valve opening degree is controlled by the signal amplitude) ； Inside the valve, a servo amplifier converts signals into motor drive current to open and close the valve, and internal negative feedback is used to position the valve. Increment (floating-point) signals are two-bit signals. The floating-point electric valve has 3 wires: a common terminal, one wire connected to the power supply for forward operation, and one wire connected to the power supply for reverse operation. The opening degree of the valve is controlled by the power supply direction and the duration of power application (increment). Floating-point electric valves, combined with a valve position feedback mechanism and PLC, can achieve precise positioning. But it is more commonly used for the control of solenoid valves and on-off valves. .

I’ve learned it, thanks! Are incremental and floating-point signals the same signal?

. Increment and floating-point signals should not be the same signal. I’m not sure how to answer this question; I can only share my own understanding. Perhaps it needs further discussion. Increment refers to the amount of change, that is, the difference between the function values corresponding to different values of the independent variable over a certain period of time. Specifically, the incremental signal for a valve should represent the relationship between the duration for which the valve’s open/close signal is active and the change in the valve’s stroke (degree of opening) ； A floating-point signal is a type of digital signal. Based on the above definitions, an incremental signal and a floating-point signal are likely not the same type of signal. Personally, I think: press the button to move the valve in one direction, release the button when it reaches the appropriate position, and the valve will stop. Alternatively, turn the switch to the on (off) position, allowing the valve to open (close) until it stops automatically at the limit (these controls can be performed remotely or on the valve actuator). It belongs to incremental control ； The valve is controlled through a simple negative feedback control system (using the valve position feedback signal as the measurement value, the desired valve position as the setpoint, and an incremental signal with a variable or constant amplitude being output). From the perspective of digital control, it can be regarded as floating-point control. Here: The setpoint signal of a negative feedback control system is fixed or variable, and this is what determines whether the system operates in follow-up control mode or constant-value control mode (floating-point or fixed-point) ； Negative feedback control systems can be constructed outside the valve or inside the valve. When it is built inside the valve, it is sufficient to send a position signal to the valve; the valve will then automatically assume that position (this position signal can also be in the range of 0–10V or 4–20mA). The control system can be digital or analog. Manufacturers play with conceptual terms; as long as it’s not limited to the kind of incremental control mentioned above, it can all be called a floating-point valve. For example, using an encoder as the valve position feedback element will suffice. .

Incremental signal: Controlled by the duration of relay contact?