Servo motor torque mode test

Main idea

The servo motor torque mode test is a method to verify that basic parameters and wiring are correct. The target is to rotate/move the motor in torque mode in a continuous manner.

Assumptions

• All wiring are triple checked and torque tuning is done properly.
  • Refer to the product user guidebook for detailed wiring instructions.
  • Pay special attention to encoder operating voltage (VCC) and GND wiring. Wiring VCC and GND erroneously may damage the encoder.
• The motor is free to move/rotate, and no harm nor damages can happen from a long continuous movement.

Steps

1. Read servo tuning basics to get understanding how servo motors work.
2. Set the drive in Torque mode from Granity.
3. Follow the torque controller tuning instructions.
4. Increase the target setpoint to get the motor moving.
   1. Go to Granity/Testing tab.
   2. Make sure that the setpoint is zero and the drive is enabled and ready.
   3. Set the [TSP1] Target setpoint 1 to 500.
   4. Increase the target setpoint slowly by clicking the "Increment by TSP1" button and checking whether the motor moves of not.
   5. If the motor moves in a continuous manner, all parameters and wiring are correct.

Troubleshooting

In most cases, the motor halts after a short movement if the feedback resolution is incorrect, or if it's direction is reversed.

• Check wiring, especially logic and motor voltages, Enable, and STO.
• Check FBI Invert feedback direction checkbox in Granity/Machine tab, and repeat the steps above.
  • This inverts the encoder direction without the need for rewiring.
• Check the motor pole count and encoder resolution from their datasheets.
• Move the motor by known angle/distance, and check the position feedback reading from Granity/Testing tab.
  • The position feedback value is always in CPR (counts per revolution). From this, the correct PPR can be calculated for one revolution (PPR = CPR/4).

Further reading

After the torque mode is configured and the motor can be controlled in torque mode properly, velocity and/or position modes can be tuned. Please refer to their respective instruction pages for further details.

• Tuning velocity controller
• Tuning position controller

Other motor types

• For linear motors, please refer to linear motor configuration instructions.
• For stepping motors, please refer to stepping motor configuration instructions.

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