A method of determining a gap between an eddy current proximity transducer and a target is provided. The device has a body, at least one pin movably coupled to the body for securing the body to a support surface, and an actuator coupled to the body and arranged to move the pin between a first position and a second position. The variable viscosity fluid can include a shear stiffening material that increases in viscosity as a load or strain, or rate of loading or rate of strain, applied, or a magneto or electro rheologic fluid responsive to a magnetic or electric field. A SMM may include one or more acquiring modules, which may be configured to determine one or more current memory states. The invention relates in particular to a rotary lobe pump in which the inlet opening and the outlet opening are arranged on a connection casing.