How to control dynamixel (XM430-W350-T) using pixhawk 6C

I want to control dynamixel using pixhawk 6C.
I followed same procedure in ardupilot doc - [Robotis Servos — Copter documentation]
I used XM430-W350-T Dynamixel, connected Tx pin of pixhawk telem 2(serial2) port( Tried other serial ports also).
Baud rate of dynamixel -57600bps
ID - 11
Protocol 2
Pixhawk 6C( hexacopter X config, Firmware version - 4.3.2)

I checked the Tx pin output in oscilloscope, I can’t see any UART signal.
Please help me to figure it out.