Can two single-loop controllers form a split-range controller?
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There are two control valves at the site that require proportional control, but no advanced controllers are available; only a few digital display single-loop controllers exist. Is it possible to use two or more regulators to achieve the function of a proportional controller?
A split-control system is one regulator controlling two control valves. What can be called a split-range control system when using two regulators?
The key point is that there are no regulators with proportional control functionality on site; only single-loop controllers are available. My question is: can this proportional control function be achieved using single-loop controllers?
I don’t understand what you mean. Step control system: The output of the regulator is sent to two control valves; one valve operates at 4–12 mA, while the other operates at 12–20 mA.
It seems that’s what the original poster meant – does doing this count as segmented control? I don’t think so. The reason for using multiple valves is that the adjustable range of a single control valve is insufficient, so two control valves are needed for control. Is that so? Let’s discuss it. Is the adjustability ratio of the segmented circuit control valve a product relationship? Is it possible to do this? Are the flow ratios of these two valves adjustable in the same way, so that it’s the same as having two single-loop systems? Right? Feel free to communicate.
Existing regulators have only one input and one output; they do not possess the capability of having one input and two outputs. What I mean is whether it’s possible to use two such regulators to achieve a split-range control effect.
Step control involves dividing the regulator’s signal into segments to control two valves. If the poster uses a pneumatic valve, one regulator is sufficient; the task of stage control is carried out by the valve positioner.
Do you mean, OP, to use two single-loop regulators to control the two valves respectively, in order to achieve an effect similar to split-range control? Does your regulator have an output selection function? One outputs 4–12mA, and the other outputs 12–20mA? Or does your locator have such a function?