How to draw the interlocking logic diagram of the pressure transmitter interlocking pneumatic control valve?
Thread Content
Xiaobai asks for advice! I have never drawn an interlocking logic diagram before, so I don’t know how to deal with it. As shown in the figure, when the pressure is 0.5KPa, the regulating valve PV 5301A is fully open, slowly closes as the pressure increases, and is fully closed at 1.5KPa. ； The regulating valve PV 5302A opens slowly at 2.2KPa and fully opens at 3KPa. How to draw such interlocking?
This has a dead zone, and the air-closing/air-opening valves are controlled separately, not interlocked. It can be realized by adjusting the electric valve positioner. On the P&ID diagram, just connect the signals to the two control valves.
You can refer to HG/T 20505 Chemical Industry Standard for Functional Signs and Graphical Symbols of Process Measurement and Control Instruments. There are cases in it.
If this is the case, then there is no need to draw interlocking, thank you!
Is this possible?: When the pressure is greater than 0.5 and less than 1.5, assign the pressure value to variable a (range 0.5-1.5), and variable a and regulating valve 1 perform PID control. When the pressure is greater than 2.2 and less than 3, assign the pressure value to variable b (range 2.2-3), and variable b and regulating valve 2 perform PID control?