Feedback is provided to the user; are notifications given by the system about the situation or action taken. In short, feedback; is the output from the system corresponding to the input of information or as support. Information about whether the system is operating or whether an action is performed correctly or incorrectly is provided to the user as feedback.
For feedback loop operations, called Feedback devices; need feedback devices. To monitor the process, they send a signal back to the driver or motion controller. There are two main feedback devices outlined in motion control applications. These are known as decoders and encoders. The solver is an electromagnetic feedback device that converts the angular shaft position into analog signals. The signals can be processed in a variety of ways, such as an RDC (analyzer to digital converter), to generate digital position information.
There are two basic types of resolver. They are designed as a transmitter type for the primary excitation of the transmitter rotor and the secondary outputs of the stator. Location; sine output amplitude to cosine output amplitude. For stator primary excitations and secondary output of the rotor, a receiver type is designed. The position is determined by the phase shift between the rotor output signal and one of the primary excitation signals.
Functions of Encoders
The most popular Feedback devices are encoders. The encoder is used to convert linear or rotary displacement to a corresponding set of digital signals. The encoder; can also be used to convert displacement to analog output voltage; is an electromechanical device.
Feedback devices The feedback devices can be basically analyzed in two ways. These; The classes are “Rotary” or “Linear”. The shape of the device does not change its operating principle.
Quadrature encoders are the most common feedback device type in servo motors today. Quarterly encoders are incremental sensors. Therefore, to obtain absolute position feedback, position reset or positioning is required.
Another type of encoder is absolute encoders. Absolute encoders typically provide serial data of the absolute position. Therefore, in the case of multi-turn absolute encoders; they may not need to be reset. The disadvantage of absolute sensors is usually higher prices and lower compatibility and interchangeability.
Analysis is an analog technology based on a rotary transformer capable of providing absolute position. Solvents are good for harsh conditions; however, they do not provide as high-precision feedback data as encoders.
Using the Tachometer
Tachometer; It is a small DC generator that gives DC voltage proportional to the rotational speed. It can be used as a speed feedback device, but not as a position sensor. Tachometers are often seen in dual-loop configurations with a position sensor.
Features of Hall Sectors
Hall sensors are usually found only on AC and BLDC motors. Like all GD drives, modern drives do not require Hall sensors. However, it can use them to make it possible to run faster. Hall sensors; very low resolution for position or high performance speed control. Therefore, Hall sensors; typically combined with encoders.