We used ROS kinetic on an Ubuntu 16.04 system to control 18 dynamixel servos through an ArbotiX-M micro-controller on which ros.h is running. After we programmed the robot to walk we now would like to measure the joint torque while walking. We tried using the infodump.py from the dynamixeldriver package but it cant find the servos:

~/catkin_ws/src/dynamixel_motor/dynamixel_driver/scripts$ python info_dump.py --port=/dev/ttyUSB0 --baud=57600 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Pinging motors:
1 ... error
2 ... error
3 ... error
4 ... error
5 ... error
6 ... error
7 ... error
8 ... error
9 ... error
10 ... error
11 ... error
12 ... error
13 ... error
14 ... error
15 ... error
16 ... error
17 ... error
18 ... error
ERROR: None of the specified motors responded. Make sure to specify the correct baudrate.

After trying to ping them the walking-program crashes, too. We also tried pinging our servos with the program mixcell which could not find them either.

Is there a way to get those torque-values, or voltage of each servo?