SLLU364 may   2023 MCT8315A

 

  1.   1
  2.   Abstract
  3. 1Revision History
  4.   Trademarks
  5. 2Introduction
    1. 2.1 Hardware and GUI setup
      1. 2.1.1 Jumper Configuration
      2. 2.1.2 External Connections
      3. 2.1.3 Connecting to the GUI
        1. 2.1.3.1 Connect to computer
        2. 2.1.3.2 Connect to the GUI
        3. 2.1.3.3 Verify Hardware Connection
  6. 3Essential Controls
    1. 3.1 Recommended Default Values based on application
    2. 3.2 Device and Pin Configuration
      1. 3.2.1 Speed input mode
    3. 3.3 Algorithm configuration – Motor speed
      1. 3.3.1 Maximum motor electrical speed (Hz)
    4. 3.4 Control Configuration
      1. 3.4.1 Cycle by cycle current limit (ILIMIT)
    5. 3.5 Testing for successful startup into closed loop
    6. 3.6 Fault handling
      1. 3.6.1 Abnormal Speed [ABN_SPEED]
      2. 3.6.2 Loss of Sync [LOSS_OF_SYNC]
      3. 3.6.3 No Motor Fault [NO_MTR]
      4. 3.6.4 Cycle by cycle current limit [CBC_ILIMIT]
  7. 4Basic Controls
    1. 4.1 Device and pin configuration
      1. 4.1.1 Power saver or sleep mode for battery operated applications
      2. 4.1.2 Direction and Brake pin override
    2. 4.2 System level configuration
      1. 4.2.1 Tracking motor speed feedback in real time
      2. 4.2.2 Monitoring power supply voltage fluctuations for normal motor operation
    3. 4.3 Control configurations
      1. 4.3.1  Initial speed detection of the motor for reliable motor resynchronization
      2. 4.3.2  Unidirectional motor drive detecting backward spin
      3. 4.3.3  Preventing back spin of rotor during startup
      4. 4.3.4  Faster startup timing
      5. 4.3.5  Improving speed regulation
      6. 4.3.6  Stopping motor quickly
      7. 4.3.7  Faster deceleration
      8. 4.3.8  Preventing supply voltage overshoot during motor stop and deceleration
      9. 4.3.9  Protecting against rotor lock or stall condition
      10. 4.3.10 Maximizing thermal efficiency and increasing thermal performance
      11. 4.3.11 Mitigating Electromagnetic Interference (EMI)
      12. 4.3.12 Improving Motor efficiency
      13. 4.3.13 Limiting and regulating supply power

4.3.9 Protecting against rotor lock or stall condition

Follow below recommendations based on the type of fault triggered by MCT8315A.

Case 1: Follow below recommendations ff motor gets locked due to LOCK_LIMIT fault. Device triggers LOCK_LIMIT fault when the motor accelerates in closed loop or when the motor is overloaded.

Step 1: Increase lock detection current threshold [LOCK_ILIMIT]

Step 2: Increase the Lock detection current limit deglitch time [LOCK_ILIMIT_DEG] if the motor can withstand [LOCK_ILIMIT] for [LOCK_ILIMIT_DEG] time.

Step 3: Decrease CL_ACC.

Step 4: Enable dynamic degauss.

Case 2: Follow below recommendations if the device triggers CBC_ILIMIT, MTR_LCK, LOSS_OF_SYNC or ABN_SPEED.

Step 1: Increase CBC current limit

Step 2: Decrease CL_ACC.

Step 3: Enable dynamic degauss.

Case 3: If the motor vibrates and device fails to detect any fault, set the abnormal speed threshold to a value slightly above maximum speed. For example, if the maximum speed is 1000 Hz, set the abnormal speed threshold to 1100 Hz.

Case 4: If the motor generates high frequency noise and device fails to detect any fault, set the maximum degauss window [DEGAUSS_MAX_WIN] to either 15°or 18°. Default value is 22.5°.

Case 5: If the motor is loaded at lower speeds, MTR_LCK fault might get triggered when Min duty cycle is set too low. We recommend to se the Min duty cycle after loading the motor at lower speeds.

Note:

MCT8315A provides options to either latch LOCK_LIMIT fault or auto retry for [AUTO_RETRY_TIMES] after every [LCK_RETRY] seconds. This can be configured in LOCK_ILIMIT_MODE. We have defaulted the auto retry time and lock retry.