Level Measurement in Active Reservoir

A level sensor with three contacts at different heights is used for the active reservoir. The plausibility of the sensor is checked in the evaluator in that it checks whether the signals are logical.

For example, it is improbable that the "Full" contact is covered by the solution while the "Empty" contact is not. In this case, the evaluator sends a plausibility error to the DDE. This takes place at a pulse duty factor of 30% of the PWM signal. A reversible fault is set. If the fault is determined in two successive driving cycles, an irreversible fault is stored and the MIL is activated.

This monitoring procedure only takes place if the temperature in the active reservoir is above a defined value.

If the line between the evaluator and at least one contact of the level sensor is interrupted, the fault is signalled to the DDE by a PWM signal with 40% pulse duty factor. A reversible fault is set.

If the fault is determined in two successive driving cycles, an irreversible fault is stored and the MIL is activated.