Mode 1, Manual Operation The vacuum valve is closed when the pressure reaches the setpoint. Closed-loop control between the set hysteresis and the setpoint has been started. For operation with a frequency converter, an analog voltage is output, which controls the speed according to the standard tolerance. If the set pressure is not reached, the speed is automatically adjusted to the pressure loss. If the pressure is actively lowered, after the setpoint has been reached for the first time, it is lowered still further within a settable timeframe. The number of ramps can be set up to a maximum of 3. Each ramp starts with a holding time. The setpoint then falls in one step to the defined starting pressure. The setpoint then falls to the final value over the set time. After the last ramp, there is a waiting time until the automatic STOP (0 – the last set pressure is held indefinitely until STOP is pressed manually).