BP1

General operational description:

The volume booster and proportional pressure regulator are fed by the supply
pressure. When no command signal is applied the outlet pressure
behind the booster is zero. When the command signal is increased
the outlet pressure rises in proportion to it.

Since the transmission ratio is not exactly 1 to 1, a slight
pressure difference occurs between the outlet pressure of the
proportional pressure regulator and the booster’s outlet on single loop systems.

This can be balanced by a feedback signal (double loop), though.
At single loop combinations the pressure difference between command
signal and outlet pressure is being ignored because the proportional
pressure regulator only refers to its own outlet pressure within the pilot chamber.
The outlet pressure performance is dependent of the volume booster’s
accuracy.