METHOD AND DEVICE FOR DETECTING STEP LOSSES OF A STEP MOTOR

摘要

For actuating a step motor, a pulse width-modulated current (S1) is fed to a coil (3) of the step motor and it is detected whether the current (IM) flowing through the step motor is within a current band width defined by an upper switching threshold (OG) and a lower switching threshold (UG) in relation to a specified value (S4b). The current supply (S1) to the coil (3) is turned on if the detected current (IM) has dropped to the lower threshold value (UG) and is turned off if the detected current (IM) has risen to the upper threshold value (OG). In order to detect a step loss (SV), the signal path of the current (IM) or the change thereof is analyzed and the deviations from the target values or target value ranges that are caused by the step losses are detected. The determination of the signal path of the current (IM) or the change thereof can be carried out indirectly by analyzing a corresponding control signal (S7).