Method for operating a device for the dosed supply of a liquid, at least having - at least one pump for delivering the liquid, wherein the at least one pump has a pump housing with at least one inlet and at least one outlet, wherein an eccentric is arranged on the pump housing and wherein a deformable diaphragm is arranged between the pump housing and the eccentric, wherein the deformable diaphragm and the pump housing delimit at least one delivery path from the at least one inlet to the at least one outlet and form at least one seal of the delivery path, wherein the at least one seal is displaceable along the delivery path by way of a movement of the eccentric for the purpose of delivering the liquid; - and further having at least one pressure sensor which is connected to the outlet of the pump, wherein the method has at least the following steps: a) delivering liquid by way of the pump; b) monitoring, during the delivery, a temporal pressure profile of the pressure at the outlet of the pump by way of the at least one pressure sensor; c) establishing an angle position of the eccentric of the pump on the basis of at least one characteristic feature (14, 15) of the temporal pressure profile at the outlet; wherein the pump has at least one Hall sensor by way of which a change in angle position of the eccentric can be detected, wherein the method further comprises the following step: d) determining a changed angle position, starting from the angle position determined in step c), on the basis of the change in angle position established by way of the Hall sensor. - at least one pump for delivering the liquid, wherein the at least one pump has a pump housing with at least one inlet and at least one outlet, wherein an eccentric is arranged on the pump housing and wherein a deformable diaphragm is arranged between the pump housing and the eccentric, wherein the deformable diaphragm and the pump housing delimit at least one delivery path from the at least one inlet to the at least one outlet and form at least one seal of the delivery path, wherein the at least one seal is displaceable along the delivery path by way of a movement of the eccentric for the purpose of delivering the liquid; - and further having at least one pressure sensor which is connected to the outlet of the pump, wherein the method has at least the following steps: a) delivering liquid by way of the pump; b) monitoring, during the delivery, a temporal pressure profile of the pressure at the outlet of the pump by way of the at least one pressure sensor; c) establishing an angle position of the eccentric of the pump on the basis of at least one characteristic feature (14, 15) of the temporal pressure profile at the outlet; wherein the pump has at least one Hall sensor by way of which a change in angle position of the eccentric can be detected, wherein the method further comprises the following step: d) determining a changed angle position, starting from the angle position determined in step c), on the basis of the change in angle position established by way of the Hall sensor. a) delivering liquid by way of the pump; b) monitoring, during the delivery, a temporal pressure profile of the pressure at the outlet of the pump by way of the at least one pressure sensor; c) establishing an angle position of the eccentric of the pump on the basis of at least one characteristic feature (14, 15) of the temporal pressure profile at the outlet; wherein the pump has at least one Hall sensor by way of which a change in angle position of the eccentric can be detected, wherein the method further comprises the following step: d) determining a changed angle position, starting from the angle position determined in step c), on the basis of the change in angle position established by way of the Hall sensor.