Sometimes, you plug everything together and it does not work, or not as well as supposed…
Here are some common points to check before asking for more help.
The most usual culprits are:
yet a huge number of other things can go wrong. Here we look at a lot of them.
The best tools are a logic analyzer, an oscilloscope, a USB interface (USB2AX, USB2Dynamixel) and a reliable way to give power to the servos.
The power supply should have a voltage in the acceptable range for the servo (see the manufacturer documentation as different servos have different voltage requirements).
The power supply needs to be able to deliver enough current to power the servos. As a rule of thumb, you should start by testing one servo with with a >1A supply. If it works and adding more servos causes problems when they start to move it can mean that the power supply is not powerful enough.
The behavior of the servos change with some internal parameters. It is necessary to make sure all servos on a same bus are set up in a coherent way.
To set these parameters, you can use:
PC running Windows + USB2AX or USB2Dynamixel + Dynamixel Wizard
PC + USB2AX or USB2Dynamixel + custom code
Arduino or similar running a Dynamixel sketch
It is better to start with a setup that you know works, like the first option.
Check that every servo has the same baud rate and that it is coherent with the one used by the master.
Check that no two servo have identical IDs. When you buy the servos, they all have the same ID: 1!