Results 1 to 10 of 10

Thread: Ax-12a change Baud rate to 115200 ?

  1. #1
    Join Date
    Oct 2011
    Location
    United States
    Posts
    158
    Images
    1
    Rep Power
    29

    Ax-12a change Baud rate to 115200 ?

    Like the title says , how would I change the Baud Rate on an Ax-12a to 115200

    Controller = Robotis Cm-700 and I am using a LN-101 USB Downloader


    Help appreciated
    -Regards

  2. #2

    Re: Ax-12a change Baud rate to 115200 ?

    Never tried using 115200 nor that hardware, so not sure how well it would work, maybe others have?

    But in theory, you could set the Servo baud rate register (4) to: 16 (0x10) which will set the actual baud rate to: 117647.1 which is off by -2.124% there manual mentions that a maximum 3% error is allowed in UART communications. Personally I try to avoid over 1.5% error as the other end may also not be exactly at 115200 either... But then again if both sides are of similar setup where they both error in the same direction, then no problem...

    Note: In order to set register 4 you will first need to be able to talk to the servo at the baud rate the servo is currently is configured for, which is most likely 1000000.

  3. #3
    Join Date
    Oct 2011
    Location
    United States
    Posts
    158
    Images
    1
    Rep Power
    29

    Re: Ax-12a change Baud rate to 115200 ?

    Thank you for the help

    I have the manual for the Ax-12a and looked at the baud rate table the problem is I am not a coder and do not know the exact syntax argument to set the baud rate to 115200 you said
    "you could set the Servo baud rate register (4) to: 16 (0x10)"


    How would I do this? I can talk to the servo with RoboPlus Terminal what is the exact syntax argument ?

    do I type :
    Baud Reg 0x10
    or
    Baud Rate 0x10
    or
    Baud Reg 16 (0x10)

    ??????
    Thanks




  4. #4
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,297
    Images
    27
    Rep Power
    278

    Re: Ax-12a change Baud rate to 115200 ?

    If you do change the baudrate, you will not be able to use any of the servos with RoboPlus Task or RoboPlus Motion - they are hardcoded to interact only with dynamixel devices using 1Mbps baudrate for the buss.

    Open RoboPlus Manager, click the connect button, and look through the list of servos found by the CM-700 (RoboPlus Manager via CM-5/510/530/700 will only find dynamixels using 1Mbps baudrate). It will list every single parameter in the servo's register table - each entry with a clear label and easy selection of the value within the limits of the parameter.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

  5. #5
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,297
    Images
    27
    Rep Power
    278

    Re: Ax-12a change Baud rate to 115200 ?

    ...or rather, the Robotis RoboPlus firmware of the CM-5/510/530/700 is hardcoded to use a baudrate of 1Mbps on the dynamixel buss.
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

  6. #6
    Join Date
    Oct 2011
    Location
    United States
    Posts
    158
    Images
    1
    Rep Power
    29

    Re: Ax-12a change Baud rate to 115200 ?

    Roboplus Manager was what I tried before I made my post no where in the data table is "Baud Rate" I have enclosed 2 screen shots.

    That is what led me to think it needed to be set via a command in roboplus terminal.

    The reason I want to change the Baud rate to 115200 in the first place is so I can experiment with this servo on a Roboard RB-110
    the code example for the RB-110 calls for the servo to be set at 115200. At present time the only way I have to talk to the servos is the robotis software.

    -Regards

    Click image for larger version. 

Name:	Capture1.JPG 
Views:	374 
Size:	66.7 KB 
ID:	6264Click image for larger version. 

Name:	Capture2.JPG 
Views:	497 
Size:	67.0 KB 
ID:	6265

  7. #7
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,297
    Images
    27
    Rep Power
    278

    Re: Ax-12a change Baud rate to 115200 ?

    Quote Originally Posted by Ron View Post
    Roboplus Manager was what I tried before I made my post no where in the data table is "Baud Rate" I have enclosed 2 screen shots.

    That is what led me to think it needed to be set via a command in roboplus terminal.

    The reason I want to change the Baud rate to 115200 in the first place is so I can experiment with this servo on a Roboard RB-110
    the code example for the RB-110 calls for the servo to be set at 115200. At present time the only way I have to talk to the servos is the robotis software.

    -Regards
    Doh. Somehow I managed to not follow through the consequences of Robotis hardcoding the firmware baudrate for the dynamixel buss (no ability to change it in manager, but can with USB2Dynamixel using RoboPlus Dynamixel Wizard). Not entirely sure how how to change it with RoboPlus Terminal since it is talking to the RoboPlus Task program running on the CM-700 and not the dynamixel buss; there is a pass through mode, but would require you to build the entire dynamixel packet. If you do not want to buy a USB2Dynamixel to use with the Dynamixel Wizard, then one method would be to use RoboPlus Task and it's direct access command to set register address 0x04 to the correct one byte value (e.g. 'ID[1]:ADDR[4(b)] = 16'). Once you run this, you will not be able to access the servos again through the CM0-700 without using custom firmware to use the buss at a new baudrate (will require the RB-110, a USB2Dynamixel/USB2AX to reset the baudrate, or some other sort of microcontroller to access the buss and change the register value back to '1').
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

  8. #8
    Join Date
    Oct 2011
    Location
    United States
    Posts
    158
    Images
    1
    Rep Power
    29

    Re: Ax-12a change Baud rate to 115200 ?

    Ahhh ha !!
    Ok thats the answer I was looking for , now the decision of do I want to actually do it. Seeing it is a 1 way trip, in case I am unable to get the RB-110 to speak to it , hehe so its a $50 gamble (price of USB2Dynamixel) I used to have a USB2Dynamixel but I think I gave it away as part of the deal when I sold my Cm-510 a couple of years ago. Thanks again for your solution.
    Best regards
    -Ron

  9. #9
    Join Date
    Sep 2010
    Location
    ಠ_ಠ
    Posts
    2,297
    Images
    27
    Rep Power
    278

    Re: Ax-12a change Baud rate to 115200 ?

    An arduino can work just as well, or build your own USB2Dynamixel with an FTDI dongle (FT232RL) and a couple logic ICs to do the full-duplex to half-duplex conversion (documented at plenty of other places online and a few times on the forum). Once it is changed, the RB-110 can be used to change it back. Could also easily upload some new firmware for the CM-700 to change the baudrate back (cm-510/700 easy-functions).
    Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
    "You have failed me, Brain!"
    bleh
    more bleh

  10. #10
    Join Date
    Oct 2011
    Location
    United States
    Posts
    158
    Images
    1
    Rep Power
    29

    Re: Ax-12a change Baud rate to 115200 ?

    Interesting, I was un-aware of "easy functions" I will look at that for sure. My current project is a rover and I am wasting a cm-700 on it to just control 2 servos. I have the RB-110 laying around and if I could get it to control the servos instead of the cm-700 it would free up that controller. I need it for my rx-24f servos. I also like the arduino idea I was recently looking at the arduino yun. Thanks again tician.
    -best regards

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. AX12A Baud Rate
    By DVS in forum DYNAMIXEL & Robot Actuators
    Replies: 5
    Last Post: 08-18-2013, 12:44 PM
  2. Dynamixel AX-12 - Resetting Baud Rate?
    By MaelXD in forum DYNAMIXEL & Robot Actuators
    Replies: 5
    Last Post: 07-22-2013, 06:00 AM
  3. Question(s) ArbotiX baud rate(s)?
    By Pi Robot in forum Arbotix, Microcontrollers, Arduino
    Replies: 5
    Last Post: 09-12-2010, 06:56 PM
  4. bioloid id change >?
    By openmindedjjj in forum Humanoids, Walkers & Crawlers
    Replies: 13
    Last Post: 07-09-2008, 09:56 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •