Starter code with [TxRxResult] There is no status packet!

Technical Support
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1

Hello,

I’m trying to control two Dynamixel MX-64AR (RS-485 version) using a Raspberry Pi and a U2D2 connected to the RS-485 port. The motors are powered at 12 V using an FA-403 power hub, and the U2D2 is connected to the Raspberry Pi via USB. However, whenever I run my Python read_write.py script (based on the official Dynamixel SDK examples), I always get the error:

[TxRxResult] There is no status packet!

I can see the device /dev/ttyUSB0 correctly, and I’ve given it full permissions (chmod 777 /dev/ttyUSB0).
Still, the motor does not respond to any command.

I’ve also tried the example on Windows, but still doesn’t work.

IMPORTANT NOTE: using Wizard 2.0, the motors work correctly.

Any advice on what might cause the “no status packet” error in this setup would be greatly appreciated.

Thank you in advance!

2

Hello dinarfil09

Here are a few things tocheck;

  1. Baud rate and ID of Actuator match your code
  2. Make sure the protocol (1 or 2) of the code matches your actuator
  3. Make sure you enable torque before trying to give it movement commands - [python]
    1. ADDR_TORQUE_ENABLE = 64 # for Protocol 2.0
      TORQUE_ENABLE = 1