Implementation method of interlocking between pumps and control valves in Zhejiang University’s control system
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Using Zhejiang University’s system, it is required that the outlet valve of the pump be opened simultaneously when the pump starts. How can this be achieved in programming? Are there several ways to do this?
The pump’s switch signal DI can be fed into the DCS system, while the digital output of the control valve is represented by DO; when DO is set to ON, the control valve is fully open. The interlock relationship can be understood as follows: if the pump is operating (DI=ON), then DO should be set to ON. There are many ways to configure it, such as using ladder diagrams, function block diagrams, or programming languages.
It should also be noted that the valve should be opened first and then the pump, and the pump should be turned off first before the valve is closed.
ST segments can be added in the “Algorithms” section of the software to achieve interlocking between the system pump and the control valves.
The issues mentioned on the 3rd floor require attention! Pump startup and valve opening can be carried out within the DCS; of course, two DO points are required. In the interlock logic, a timer is added after the pump startup command, while the valve is opened directly. When shutting down the pump, the valve is closed in advance!
Was the 3rd floor mentioned incorrectly? Outlet valve? The pump should be started first to build pressure for 1-2 seconds before the valve is opened. When shutting down, the valve should be closed first and then the pump stopped to prevent liquid from flowing back and hitting the pump blades