The Right Angle Encoder for Reliable Processes

Choosing the right encoder and intelligently using machining process data are key factors in the reliability, stability, and accuracy of production processes. A new demonstration unit from HEIDENHAIN will immerse you in the unique characteristics of different encoder models.

How the demonstration unit works

Analyzing the positioning behavior of four different angle encoders on a TMB+ torque motor from ETEL reveals the effect of signal quality on dynamic performance and the effect of the measuring principle on accuracy. The demonstration unit contains typical examples of absolute angle encoders used in machine tools.

  • The RCN 8311 sealed encoder from HEIDENHAIN
  • The ECA 4410 modular optical encoder from HEIDENHAIN
  • The ECM 2410 modular magnetic encoder from HEIDENHAIN
  • The WMxA 1010 inductive encoder from AMO  

A decisive effect on surface quality

A comparison of the motor current noise starkly reveals the different motor behavior with different encoders. Optical encoders cause low, steady noise, whereas magnetic and inductive encoders cause higher, much more heterogeneous noise, even with a low-pass filter. Optical encoders are therefore the best choice for making optimal use of a motor’s performance potential and for obtaining the best-possible surface quality. That’s because an encoder’s signal quality has a direct impact on multiple aspects of direct-drive motor behavior:

  • The current noise
  • The attainable dynamic performance
  • The potential power dissipation
  • The thermal behavior

The desired versus the actual position

The WMxA inductive angle encoder exhibits a particularly high level of error in dynamic positioning accuracy when measured at the attainable contouring accuracy. This deviation is a by-product of the inductive scanning method, which causes varying accuracy based on speed. In contrast, the RCN and ECA optical encoders demonstrate hardly any deviation between the desired and actual position. The ECM magnetic encoder exhibits mid-level performance without extreme error.  

Intelligent motor protection for reliable machining processes

Torque motors such as the TMB+ from ETEL feature very high performance in a compact design. However, if the current distribution in the windings is asymmetric during certain machining situations, the temperature of a single winding can suddenly surge, causing an overheating risk. The EIB 5200 sensor box from HEIDENHAIN monitors all three windings of the motor, making the temperature data immediately available for use. Intelligent motor protection and high process reliability are attained by digitizing the temperature sensor data close to the application and transmitting it to the control.

Would you like to find out more about the right angle encoder for your machine tool? Receive a personal consultation:

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