Stegmann - Incremental Encoders - Glossary of Encoder Terms

Servo Motor Feedback Systems

Comparison of Feedback System

Comparison Chart of Conventional Feedback Systems The Initial Situation Depending on their design and application, electric drives need the following information from corresponding signal transducers in the control loop: Commutation information Rotational speed information Incremental position information Absolute position information over several revolutions Up until the end of the nineteen-eighties a large number of different solutions were used to achieve these objectives (see overview below). The introduction of digital rotational speed control had a significant influence on signal transducers. More and more functions were being consolidated in only one signal transducer whenever possible. The Resolver, which contains virtually all the functions in one instrument, appeared to be functionally ideal. The exception here was when multi-turn absolute positional information was required. The low accuracy of the Resolver and its systembound I-behavior in the control loop are, however, precisely those criteria which stand in the way of the features which can be achieved by means of digital speed control, such as highly synchronized operation and high dynamics or load stiffness. For this reason, in turn, a multiplicity of the most diverse signal transducer designs was produced. This led to an incomprehensible number of interfaces.
Commutation only Technical design: Hall elements and motor-specific magnetic code disc Interface: parallel, in widely varying voltage designs 5-8 lines
Commutation and Tach Technical design: Hall elements and motor-specific magnetic code disc for the commutation Analog tachometer or incremental encoder for the Tach. Interface: parallel, in widely varying voltage designs both for the commutation and for the tachometer functions 7-16 lines
Commutation, Tach and incremental position Technical design: Hall elements and motor-specific magnetic code disc for the commutation. Analog tachometer or incremental encoder for the Tach, additional incremental encoder for the position Interface: parallel, in widely varying voltage designs. both for the commutation and for the tachometer functions, as well as for the position functions 10-20 lines
Commutation, Tach and absolute position Technical design: Hall elements and motor-specific magnetic code disc for the commutation. Analog tachometer or incremental encoder for the Tach, additional absolute encoder for the position Interface: parallel, in widely varying voltage designs, both for the commutation and for the tachometer functions. Synchronous serial SSI for the position functions 16-40 lines
HIPERFACE^® High Performance Interface
Why HIPERFACE^® In the table, it can be seen that different signal encoders were used, depending on the application. Reference to the volume suitability-for-use pyramid (figure, above) shows why such a large number have been produced. Account has to be taken here of the fact that until today, no signal encoder with a high suitability for use could complete in terms of price with the Resolver. Technical innovation for the highest requirements was brought into the market place by Stegmann with their SinCos® product line. From mid 1996. Stegmann will be supplementing the range of signal encoders for standard and low-cost applications with the SinCoder® product line in terms of a direct price comparison, these have not yet matched the Resolver but are about 10% less expensive in system price. SinCos® and SinCoder® are compatible in terms of their mechanical and electrical interface. Electrical compatibility is guaranteed in respect of all physical parameters by the introduction of HIPERFACE® as the mandatory interface. Benefit from the advantages of HIPERFACE^®: only one interface to the speed controller for all applications only one type of signal line between speed controller and signal transmitter only one mechanical interface for low-end and high-end applications manual parameter setting on the speed controller is dispensed with. (Intrinsic initialization)