Results 1 to 6 of 6

Thread: Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

  1. Question Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

    Hi,

    I am controlling 4 MX28-T actuators currently using protocol 1 but I am considering using protocol 2.0. Protocol 1 has the set max torque (goal torque) register and I wanted to know if there was an equivalent on protocol 2.0? The only thing I can think of is reading the load and changing the velocity to keep the load at a desired value.

    I was also wondering what the specific benefits of using protocol 2.0 over 1 are?

    Thanks in advance!

    Jasper

  2. #2

    Re: Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

    Protocol 2 allows for control of more parameters of servos that support them.
    Protocol 2 allows for "virtual mappings" of registers so if you frequently update a number of registers together, you can map them to a contiguous area which you can write in a single transaction.
    Protocol 2 has a more robust 16-bit CRC instead of 8-bit checksum.
    There are also a few other usability improvements over protocol 1 that escape me at the moment.

    I should think that all parameters supported under protocol 1 are also supported under protocol 2? What documentation are you using where it seems like they don't support max torque?

  3. #3

    Re: Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

    With questions like this, I often suggest that you ask them on the Robotis Forum: http://en.robotis.com/service/forum.php

    I assume you are looking at their control table: http://emanual.robotis.com/docs/en/d...#control-table
    versus the Protocol 1: http://emanual.robotis.com/docs/en/d...28/#max-torque

    Also protocol 2 gives you some other capabilities, like the ability to do Sync Read commands, where you only send out one packet, and each of the servos in your list will send you back a packet. Likewise for Bulk Read and Write, except in this case you can specify a different set of registers for each servo (must be continuous).

    But it goes without saying, that if your servo speaks Protocol 2, than you must use a library that understands Protocol 2...

  4. #4

    Re: Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

    I'm of the impression that the MX servos, with modern firmware, can speak both? The protocols are such that the servo can reliably tell whether you're trying to speak v1 or v2.
    Or do you need to load different firmwares for different protocol versions?

  5. #5

    Re: Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

    What I have seen and believe is if your servo is configured for Protocol 2, you must speak protocol 2.

    That is for example if I use some XL430-w250 like servos, and have one lets say ID #1.

    It will not respond to a ping of #1 on protocol 1... only on Protocol 2...

    Forgot to mention, another difference between protocol 1 and 2 is the PING message. On protocol 2 it returns some data about the servo. You can also use the broadcast ID and all of the servos in turn will respond....

    But if you have updated firmware, that speaks Protocol 2, you can configure the servo to speak protocol. 1.
    http://emanual.robotis.com/docs/en/d...otocol-version

    What I don't remember about how Protocol 2 servos work when configured to use Protocol 1. Obviously you can not access any of the registers >= 256 as the address field is only a byte in length.

    But not sure about things like: What register do you set to for goal_position and what size is this register.
    This is do you use the protocol 1 address (30 length 2) for this, or do you use address 116 length 4? ...

  6. Re: Goal torque on MX28-T protocol 2.0 & benefits of protocol 2 over 1?

    It does seem like protocol 2 may speed things up for me.

    I update the Torque limit/goal torque register on protocol 1.0 which is register 34. I can't seem to find a register that does the same thing on protocol 2.0. I was wondering if I'm wrong about this?

    I know that the goal torque on protocol 1.0 isn't massively accurate but it's proven pretty useful.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. MX-28T communications protocol
    By Involute in forum DYNAMIXEL & Robot Actuators
    Replies: 3
    Last Post: 03-09-2016, 03:38 PM
  2. Mx28 : Need help to control the goal position.
    By danyboy in forum DYNAMIXEL & Robot Actuators
    Replies: 11
    Last Post: 07-01-2013, 04:16 AM
  3. SiLabs F350D Compass Protocol
    By Adrenalynn in forum Sensors
    Replies: 6
    Last Post: 09-16-2009, 02:55 PM
  4. HMI Serial Protocol
    By Sienna in forum Humanoids, Walkers & Crawlers
    Replies: 2
    Last Post: 02-11-2009, 09:29 AM

Tags for this Thread

Posting Permissions

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