SLLA665 April   2025 MCF8315A , MCF8315C , MCF8315C-Q1 , MCF8315D , MCF8316A , MCF8316C-Q1 , MCF8316D , MCF8329A , MCF8329A-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Open Loop and Handoff Stage
  5. 2EEPROM Configurations Affecting Open Loop to Closed Loop Handoff
  6. 3Open Loop to Closed Loop Handoff Tuning
    1. 3.1 Experimental Way to Tune Open Loop and Handoff Stage
      1. 3.1.1 Step-1: Initial Configuration
      2. 3.1.2 Step-2: Tuning of Parameters In Case Handoff is not Proper
        1. 3.1.2.1 Tuning of OL_ILIMIT
        2. 3.1.2.2 Tuning of Open Loop Acceleration Co-Efficient A1
        3. 3.1.2.3 Tuning of Handoff Thresholds
      3. 3.1.3 Step-3: Tuning of Handoff Configurations
  7. 4Optimum Handoff
    1. 4.1 Open Loop Time With the Recommended Settings
    2. 4.2 Open Loop Time by Following Optimum Handoff Steps
  8. 5Summary
  9. 6References

3.1.2.2 Tuning of Open Loop Acceleration Co-Efficient A1

If the speed feedback is not able to reach open loop velocity reference even after increasing OL_ILIMIT, then the open loop A1 needs to be reduced. Further, the recommended setting is to keep OL_ACC_A1 equal to (MAX_SPEED/10)Hz/s.

For MOTOR1, the recommended setting is 50Hz/sec, if the setting is higher, there is a risk that handoff can fail. Higher OL_ACC_A1 increases the speed reference quickly, and the motor cannot track the speed reference with the given OL_ILIMIT, which can lead to handoff failure.

Handoff is Not Proper Because of Higher A1 (A1 = 50Hz/sec) Value Figure 3-4 Handoff is Not Proper Because of Higher A1 (A1 = 50Hz/sec) Value
Note: In the previous two failure cases, the waveform looks similar. So, first increase the OL_ILIMIT till motor rated current, and if still handoff is not proper, then decrease the open loop acceleration coefficient OL_ACC_A1 until handoff is proper.