Abstract: A method is presented for detecting the position and the direction of motion of a movably mounted part on an electric motor that makes provision not only for a single-channel sensor but also a measuring arrangement for the motor current and the rectified motor current by means of which the motor current is activated after operating switching devices to reverse the polarity of the voltage applied to the motor to cause a reversal of the direction of motion. The measuring arrangement establishes from the variation of the motor current over time the point of time of the motor current maximum and transmits this to the evaluation logic. The point of time of the actual reversal of the direction of motion is derived from the point of time of the motor current. Preferably, the current is measured as a reference current value even before falling through the zero crossing.

Abstract: A tunable digital filter arrangement realizes the difference equationy[n]=.alpha..multidot.(x[n].+-.x[n-1])+(1-2.alpha.).multidot.y[n-1]and in which the limiting frequency can be tuned linearly by means of only one tuning parameter .alpha.. The tuning range is limited solely by the sampling rate and bit width of the registers and can also accept in particular very low frequencies. The filter arrangement can therefore also be used in particular for prefiltering sampled and digitized measured values of the motor current for load-dependent motor control in the extremely slow speed range. By selecting "+" as the operator ".+-.", a low-pass characteristic results; selecting "-" as the operator results in a high-pass filter. It is possible to cascade several low-pass and/or high-pass filters.

Abstract: A process for controlling the closing movement of closing mechanisms with at least one electromotive part includes the following features to guarantee squeeze protection: the measured values of at least one motor performance characteristic which characterizes the load on the electric motor, are continuously recorded and evaluated, a continuously adapted tripping threshold defining a squeezing incident is specified for each motor performance characteristic, the measured values of each motor performance characteristic are compared with each tripping threshold and, if the tripping threshold is exceeded by at least one measured value, a defined reaction is initiated from the closing mechanisms.