Abstract: A method for testing a frequency converter having individual switching elements and motor connectors for each phase of the frequency converter. The method includes selectively activating the individual switching elements of the frequency converter and applying a control pattern to a control input of each phase of the frequency converter. Registering voltage patterns occurring at the motor connectors for each phase of the frequency converter, wherein the registering is performed for each of the motor connectors via a single test line that is capacitively connected to the motor connectors. Comparing the control pattern applied to the control input with the voltage patterns registered for each phase of the frequency converter. Detecting a malfunction in the frequency converter in case of a deviation of the voltage patterns, registered at the motor connectors, from voltage patterns expected as a result of the control pattern applied to the control input.

Abstract: An optical position measuring device that includes a measuring graduation and a scanning unit, which moves relative to the measuring graduation along a measuring direction. The scanning unit includes a light source, a transmitting graduation with a graduation period PAT, on which a periodic strip pattern with a strip pattern period PSM results in case of a relative movement between the scanning unit and the measuring graduation. A detector arrangement arranged at a distance DDET from the scanning graduation with a plurality of blocks of individual detector elements, wherein the plurality of blocks are arranged periodically with a detector period PDET in the measuring direction. The transmitting graduation is at the distance u from the measuring graduation, the scanning graduation is at a distance v from the measuring graduation, and the detector period PDET has been selected in accordance with the equation PDET=m*1*Pv, wherein m=(1+DDET/(u+v+DLQ)) and 1=1, 2, 3, . .

Abstract: An optical position measuring system that includes a light source, a measuring graduation, a scanning unit movable relative to the measuring graduation in at least one measurement direction. A projection graduation has periodic amplitude and phase structures disposed in alternation in the measurement direction. The arrangement further includes a detection graduation and a plurality of optoelectronic detector elements, wherein light from the light source interacts with the projection graduation so as to project a fringe pattern onto the detection graduation, so that via the plurality of optoelectronic detector elements, displacement-dependent output signals are detectable, and wherein the projection graduation has a structure such that in addition to even orders of diffraction and the zero order of diffraction, at least some of the (2n+1)th orders of diffraction are suppressed, where n=1, 2, 3, . . .

Abstract: In a position measuring device, a scale is embodied as a phase grating on which several partial beams impinge and are diffracted and caused to interfere with each other in the scanning unit. The entry angle (&agr;) of the partial beams corresponds to the Littrow angle, so that the diffracted partial beams of ±1st diffraction order are diffracted at the same angle &bgr;=&agr;. The diffraction efficiency of the scale is particularly great if the flanks of the bars of the scales are at an angle of approximately 70° with respect to the measuring direction, i.e., if the bars and gaps are embodied to be trapezoidal in cross section.