The Downstream Ramp Generator [4] generates a ramp-shaped output signal from the step input signal.

The time constant of this signal can be adjusted to ramp up and ramp down using two potentiometers.

The specified ramp time is related to the command value step change of 100% and can be about 1 sec. or 5 sec.

depending on the jumper setting. If a command value step change of less than 100 % is applied at

the input of the ramp generator or when the attenuator [3] is set, the ramp time can be adjusted upwards and downwards.

or when the attenuator [3] is active, the ramp time is shortened accordingly.

With the aid of the external contact “ramp up/down”, the ramp time can be set to a minimum

value (approx. 30 ms) for the upper and lower ramp times respectively.

The output signal of the Ramp Generator [4] is an internal current command value and is fed

into the measurement socket “w” on the front panel of the card.

In addition, the command value is transferred to the current output stage [6] via the current regulator [5].

The current regulator [5] adds the value of the bias current potentiometer “Zw” (R130) to the value of the ramp generator.

The current command value is modulated by the clock pulse encoder signal [7].

The clocked actual current value acts like a constant current and superimposes a jitter signal in the valve solenoid.

The actual current value through the solenoid valve can be measured at socket “I”.

Here, a voltage of 800 mV corresponds to a current of 800 mA.