Can Dynamixel XM430-W350-T and XL330-M288-T Motors Be Used Together on the Same Bus?

[Mengzhuo_Li]

Hello,

I’m currently working on a project where I’m using two different models of Dynamixel motors: 5 XM430-W350-T and 5 XL330-M288-T. I’ve connected them to the same bus and enabled torque simultaneously, but I’m encountering a Bulk Read Fail error.

I’m wondering if this issue could be due to the different models being incompatible when used together on the same bus. These motors have different specifications, and I suspect that the communication protocol or voltage requirements might be causing the failure.

Here’s what I’ve tried so far:

• Ensured the baud rates are the same for all motors.

• Verified the power supply is sufficient for all motors.

• Attempted to read from motors individually, but the error persists when trying to read from both models together.

• All torques can be opened at the same time.The error occurs after the torques are opened.

• The newest firmware is installed in all motors. (V52 for XM430-W350-T V49 for XL330-M288-T)

• Using ros_control structure and relevant nodes for controlling.(ROS Version : ROS2 Humble)

  Has anyone had experience using these two models (XM430-W350-T and XL330-M288-T) on the same bus? Could this be a compatibility issue due to the differences in their specifications, or is there something else I should check or configure to make them work together?

Any help or suggestions would be greatly appreciated!

Thank you!

[roboteer]

In your post, you did not clearly mention how you powered your 10 DXLs. So just to be sure please read on.

First, both XM-430s and XL-330s can be “controlled” together (via 5V TTL, i.e. via a common DATA line of the standard DXL 3-pin connector/cable). However XM-430s operate on 12 V (on the VDD Line of same DXL 3-pin connector/cable) while XL-330s operate on 5 V (also on the VDD Line of the 3-pin connector). Thus their Power Circuits need to be separated (12V isolated from 3V), but their Power Circuits need to have the same ground. Basically the issue is called “Mixed Voltage Operations”. You can read a concise explanation at this ROBOTIS post:

DYNAMIXEL Daisy Chaining Quick Start Guide

[1] [2] Daisy Chain Quickstart Guide.pdf (828.3 KB)

and

How To: Wire Mixed Voltage DYNAMIXEL Daisy Chains

DYNAMIXELs can be daisy-chained together for simplified control and wiring, a feature many of you are familiar with. But, integrating servos with mixed operating voltages into a single daisy chain presents extra challenges. I wanted to shed some light on this subject and provide you with a recommended approach to tackle this task effectively. Caution: Be careful when attempting to combine DYNAMIXELs with different voltages in a daisy chain: A mistake in wiring in a setup like this can result …

or

5v and 12v motor control via 1 OpenRB-150?

I have encountered this voltage-mixing in the past and it can be easily solved if you understand the issues/principles involved. Please visit this following post to get more details, although it was written for an OpenCM-904 controller, the same approach applies for all ROBOTIS controllers. You will need to create ONE custom X3P DXL Power Cable, see this post: and ONE custom X3P cable (with VDD cut off) to serve as an “electrical isolation” between the 5V DXLs and 12V DXLs (i.e. for the 2…

So FIRST please verify that you have powered and controlled the DXLs in the proper way. BTW, what is the Controller that you use? OpenRB-150 or OpenCR?

Also as you have a total of 5 DXLs of each type, there may also be an issue of the DXL Daisy chain to be “too long” as the rule of thumb is “no more than 4 DXLs in any daisy chain”. So you can try these X3P hubs also to make 2 shorter chains of 3 and 2 for each type of DXLs. But you may be able to “get away” with only 1 DXL chain of 5 DXLs of each type, if the physical cabling is “short” within the DXL network of your robot.

3P JST Expansion Board

If you prefer a “longer” explanation of mixed voltages procedures in video format, you can check out my YouTube video for XL-330 and XL-430:

Using U2D2 with XL330s and XL430s with BIOLOID hardware