Seeking the logical control diagram for valves
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Help, everyone! There is now a control valve HV101; the pressure transmitter PT101 causes the valve to open when the pressure is above 0.5 MPa, and to close when the pressure is below 0.3 MPa. And the control room is equipped with a manual switch. Please teach the teachers how to draw a logic control chart.
First of all, thank you to all the teachers here!
There’s no need to draw this, right! It’s quite simple: write a logical program in DCS using IF THEN ELSE ENDIF statements.
Use CFCs – it’s the most basic option
It features a direct functional block structure for greater intuitiveness; the Pv value from the pressure transmitter is compared with these two set values – if it is higher, the system operates; if it is lower, it shuts down. Three intermediate variables are used, two of which are analog values for setting, and one is a digital variable for switching between manual and automatic mode
Just adjust the DCS function blocks a bit; make it something more appropriate
I’ll draw a picture for you by hand; make do with it
If a 0.4Mpa signal is applied to the interlock, will the interlock be in the on or off state?
This is just a conditional check; it has nothing to do with your original state