Sensorless step recognition process for stepping motors

Abstract

A process is disclosed for recognizing the step of stepping motors by analyzing the current that flows through the motor, without using any sensors. In order to overcome the problems caused by the use of a shunt resistance, the resulting current measurement errors and toggling, and to ensure an as disturbance-free and reliable operation as possible in all operation states of both unipolar and bipolar stepping motors, the disclosed process has the following steps: a defined current is transmitted to a motor winding after a reversal of the current flow direction in a first motor winding; a motor winding connection is switched with a high ohmic value; the response signal at the motor winding connection switched with a high ohmic value is sensed; the length of the response signal is evaluated. Alternatively, triggering is provoked by an external triggering signal, independently of the reversal of the current flow direction.

Dependencies are inferred from the claim text.