Ok I have found a bug with the CM-550 controller. I am programming it in python using task 3.1.6.
The issue is if I down load a program and run it then it works fine but if I power down the power up again many of the dynamixels don’t work until I re-download the program again.
First I was developing the code with both the main power connected(without battery) and the USB connected so everything worked fine. After I unplugged everything then plugged the battery in and tried to run it as stand alone the program ran fine but many of the dynamixels didn’t torque on. I tried reconnecting the main powers and still the same out come. I tried reconnecting th USB to computer and still same problem. As soon as I down loaded the program again it all worked. I tried repeated power down and power up cycles and always the same result whether using battery power or mains power.
I found I can run the robot fine off battery power if I power up via battery the connect USB to computer and down load then disconnect from computer and run as stand alone but any time I turn off the robot then I will need to re download the program again before all dynamixels work.