Commutation with Hall and ABI combined

Overview

An ABI encoder and a Hall sensor can be combined to function as a single encoder for commutation. This combines the benefits of a high resolution angle from the ABI encoder, with the absolute electrical position provided by the Hall sensor.

Requirements

  • The Drive needs a Hall sensor and an ABI encoder connected at two different connectors, both must be properly configured.
  • The motor phases and the Hall pins have to be connected according to the Servo drive’s documentation.
  • The ABI commutation offset has to be found before this feature starts working.

Usage

This feature is automatically enabled when there is one Hall sensor and one ABI encoder present.

The Hall sensor must be configured as Commutation only.

The ABI encoder may be configured with any of the commutation functions:

  • Commutation & Motion Control Feedback
  • Commutation & Monitoring
  • Commutation only
  • Commutation & Velocity

Detailed description

Startup

When the feature is started, the Hall sensor is sampled and it is checked if it’s in a valid state. If an invalid hall state [0, 0, 0] or [1, 1, 1] is found, an error ‘HallSeq’ is raised, and the connections should be checked.

Error Detection

Cable errors can lead to problems: if only one Hall sensor is disconnected or damaged, or if the phase signals are reversed, the problem will not be detected. Running the motor with Hall set as the only Commutation sensor can be done to ensure the integrity and proper connection of the Hall signals before integrating the ABI encoder.

Runtime

If no error is raised, the initial electrical angle is estimated based on the Hall sensors, and the Hall sensors are not sampled again. As soon as the incremental encoder passes the index, the service realigns the electrical angle to the formerly saved precise value.