POST No. 2407346
Dynamixels not detected
2019-03-15 01:52:10 abhayvar

I have a chain of 10 dynamixel servos described below:

16-14-1-11-2-15-17-13-12-9 (Dynamixel IDs)

ID           Model           Firmware


16           MX-64T              40

14           MX-26T              40

1             MX-28T              40

11           MX-28T              40

2             MX-64T              40

15           MX-28T              39

17           MX-64T              40

13           MX-28T              40

12           MX-28T              40

9             MX-64T              39

I am using dynamixel_workbench. Both dynamixel_workbench and dynamixel_sdk are latest version.

I am using U2D2, SMPS2Dynamixel and a 12V DC power source.

1. When I run find_dynamixel example in dynamixel_workbench toolbox, servo with IDs 12 and 14 are not found.

2. I tried updating firmware of 9 and 15 using Dynamixel Wizard in WIndows but it failed.

3. Dynamixel ID 12 is detected only individually while 14 is detected if 16-14-1-11-2 are connected in a chain.

4. Dynamixels with firmware v40 also use protocol 1.0 while the site mentions that v39 above will use protocol 2.0.

Kindly help we with this problem. Thanks.

2019-03-15 01:52:10
2019-03-17 22:53:26 Kurt Eckhardt

Hopefully Robotis can give you a more complete answer, but if it were me:

a) I would try to update all of the firmware, such that they are all running either protocol 1 or protocol 2.  You might try the beta Dynamixel Wizard 2: https://community.robotsource.org/t/beta-test-dynamixel-wizard-2-0/1608 as I believe it can handle both...

b) I would try to break this up such that there are not 10 in a row, but hopefully maybe use a hub to split them into smaller chains.

c) Make sure all of the servos are running at the same baud rate, and I always to try to set the return delays to 0 on the servos.

d) might also check you 12v DC power source on how much can it output?

Good luck

2019-03-17 22:53:26
2019-03-18 13:14:23 Will Son


First of all, the Firmware version does not determine which Protocol you are using.

There are different Firmware version for each Protocol version.

For example, the latest firmware version for MX-28 Protocol 2.0 is v42 while Protocol 1.0 is v40.


In order to use all DYNAMIXEL in a single channel, please use the identical protocols for all connected DYNAMIXELs.

Also, when connecting multiple DYNAMIXELs in a series, it is recommended to use power jump on every 4~5 DYNAMIXEL.

This is to prevent voltage drops as well as to reduce current flows on the cables.

For example, in your configuration, you can supply power to #16 ~ #2 and #15 ~ #9 directly from the power supply as shown below.


However, the stall torque of MX-64 can reach up to 4.1A at 12V, therefore, it is strongly recommended to use separate power source for every 2~3 Dynamixels because SMPS2Dynamixel can only supply up to 5A.

Thank you.

2019-03-18 13:14:23
2019-03-20 20:46:04 Morocco Mandula

Mentioned on Robotis Protocol 2.0 E-Manual. Here [http://emanual.robotis.com/docs/en/dxl/protocol2/#introduction].

2019-03-20 20:46:04
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