Why Do Different Control Valves Have Different Characteristics?

Some valves have an inherent characteristic that cannot be changed, such as full port ball valves and butterfly valves. For other valve types, such as globe, the characteristic can be changed to suit the application.

Ideally the inherent valve characteristic should be chosen to give an installed characteristic as close as possible to linear (see inherent vs installed characteristic). This enables the loop to remain tuned at all conditions with the same calibration settings.