MX-64 disconnect and Sync-Write issues

Hi I have a project where we’re using 2 MX-64, and the rest are of the XM-series. I was able to get syncwrite working for 1 of the MX-64 motor and the XM-series together but I keep getting a groupsync getData issue for the last MX-64 motor. When I try moving by itself, it works great up until a certain point where it shows a txpacket issue and disconnects out of nowhere (for example it’s at position 2300 and can go to 3300 but when it moves to 3400, it disconnects). What reasons could be making the MX-64 motor disconnect? Ideally I would want this MX-64 to be able to do syncwrite with the rest of the motors but I can suffice with getting the first motor working correctly without disconnecting.

I would like to make a correction, it’s actually a MX-106 that’s not working properly. I had the name mix up

@outegrals
Hi, I’m sorry for the delayed reply.
So to my understanding, you are using (x) XM series and (1) MX-64, and (1) MX-106 connected in a single channel.
Could you provide more information on DYNAMIXEL settings and your development environment?

  • Protocol version of MX-64 and MX-106, and XM-series :
  • Type of DYNAMIXEL (TTL or RS-485) :
  • The total number of DYNAMIXELs connected in the channel :
  • Software library used to control DYNAMIXEL :
  • The exact error message returned or displayed :
  • Power source (voltage and current settings) :
  • A simple description on how components are connected and powered :

Sorry for quite a bunch of questions, but these are needed in order to solve your unusual case.
Thank you!

Hi,

I am using 1 MX-64, 2 MX-106, 4 XM 430. Yes, its all connected in a single channel in the following sequence: (1) Power source -> MX-106 -> (2) MX-106 -> (3) XM-430 -> (4) MX-64 -> (5) XM-430 -> (6) XM-430 -> (7) XM-430 -> U2D2 controller

Here is the information on the dynamical settings and development environment

  • Protocol version of MX-64 and MX-106, and XM-series : All in protocol 2
  • Type of DYNAMIXEL (TTL or RS-485) : RS-485
  • The total number of DYNAMIXELs connected in the channel : 7
  • Software library used to control DYNAMIXEL : C++
  • The exact error message returned or displayed :
    If I only move motor 1 pass 90 degrees I get a timeout issue on the wizard, but if I move it all together in C++, it moves together for a bit and then get a groupsyncparam error
  • Power source (voltage and current settings) : 12V and about -20 to -24 mA (atleast that’s what it says on the wizard)
  • A simple description on how components are connected and powered :
    It’s all connected together in a daisy chain manner where the motor 1 is connected directly to the power supply and the rest of the motors to each other. The motors are inside a 3d printed arm to simulate a human arm.

Thank you for the help!

Thank you for the information.
If possible, please test these DYNAMIXELs without connecting them to the frame(robot arm) so that they are not loaded.
One thing that I’m worrying about your configuration is that you have connected high current consuming DYNAMIXELs in a series, and when MX-106 draws a lot of current such as 90 degree straight arm forward motion. you might not be able to provide enough power for the other DYNAMIXELs.
In case of high current demanding applications, it is recommended to jump the power so that there isn’t voltage drop or brown out.

Recommended cabling :
power_jump

When the MX-106 is returning a timeout, please also check if there’s any error flag in the Hardware Error Status(70).
Also check the maximum current setting of your power supply unit. Though it could be vary by your actual hardware design, your supply should at least be able to supply 12V 10A.

Thank you the advice,

we were able to take motor 1 out of the arm and confirm it was functioning normally by itself. For the recommended cabling, we have the SMPS2Dynamixel after the power supply, would we connect another wire from that to the MX-64 connection (per the diagram there are 3 connections coming out of mx-64, but it only has two ports. Or would this mean another U2D2 would be needed?

Hi,

The max power supply for SMPS2Dynamixel is 12V 5A which is way to little for all your connected DYNAMIXEL. I’d recommend to use additional SMPS2Dynamixel at the MX-64 connection.
Please note that MX-106 at it’s stall condition, it can draw up to 5.2A, and similarly with MX-64, 4.1A can be consumed when it is stalled.
Thank you.