Instrument design issues
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In the design of automatic control instruments, are the dimensions of the equipment drawn at their actual size (with scaling applied afterward)? If it is designed based on actual dimensions, what about the sizes of those instruments and valves?
Devices are generally scaled down according to their actual size. Instrument valves are represented by symbols, and there is no need to depict them in their full form; therefore, there is no issue of scale.
Flowcharts do not need to be drawn to specific dimensions, but piping diagrams must take dimensions into account, and these dimensions come from the manufacturer’s samples.
A valve symbol is sufficient; in tendering processes, it’s not necessarily the manufacturer that wins the bid!
Most control drawings are “schematic diagrams,” such as instrument layout plans and installation diagrams. . . . It shows the actual position of the instrument and the relative height difference (whether the transmitter is installed upward or downward); the size of the instrument itself does not need to be proportional. However, the size of the equipment shown on the plan should be based on its actual dimensions, calculated according to the scale of the drawing. @jiaguoyun