Encoder systems for asynchronous DRN.., DRU.., and DR2.. AC motors or servomotors

In the case of asynchronous motors, encoder systems are generally used for the following reasons:

  • Speed control – to achieve high speed quality and to respond optimally to load changes.
  • Positioning
  • Torque control
  • Speed and rotation monitoring

The following encoders are generally used here:

  • Low-resolution incremental encoders
    • Can only be used for positioning and speed monitoring and not for speed control
    • Only simple positioning (rapid/creep speed) is possible
    • As a result, the system has lower dynamics
    • Reference travel required
  • Incremental rotary encoders
    • For speed control
    • For positioning
    • Reference travel required
  • Absolute encoder
    • For positioning
    • No reference travel required
    • If no real-time channel (combi encoder with either sin/cos, TTL, or HTL signal) is present, then an additional encoder system is required for speed control.