Powering XL430 Daisy Chain from Multiple Power Sources

[nicolaskk]

Issue:

I am attempting to power a chain of XL430-W250-T motors from various power sources. I am using separate SMPS2Dynamixel boards to inject power between motors, but I am not sure if this set up is safe. Each node of the chain is as follows: 3S Lipo Battery connected to a SMPS2Dynamixel, with each 3P output of the SMPS connected to different motors. This chains continues for 12 motors. The reason I have to use separate Lipos is to extend the battery life of the robot. Unfortunately using a large lipo is not possible due to space constraints.

Do the SMPS2Dynamixel boards create a unified power rail this way or do they fight with each other?

I am trying to upload an image but I am a new user so I cant put one in. Let me know if my description is clear.

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DYNAMIXEL Servo:

XL430-W250-T

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DYNAMIXEL Controller:

U2D2, SMPS2Dynamixel

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Software Interface:

Python Libary

[roboteer]

@nicolaskk
Is your controller a PC with USB ports? And you have only 1 U2D2 to use? Also what is the rating of your LiPo battery in terms of C number or mAh rating? And the SMPS2Dynamixel has only 2 3P connectors, how many SMPS2Dynamixel modules are you using? SIX of them? Lastly, does the physical configuration of your robot use 4 groups of 3 XL-430s or 3 groups of 4 XL-430s?

Besides the Power issue, you may also have to take into account the Control issue: what is the physical distance between the U2D2 and your “farthest” servo away from the U2D2?

Please see this post also:

OpenRB-150 Power Supply Issue Inquiry

Issue: I plan to use the OpenRB-150 controller to operate six MX-28 DYNAMIXEL servos, and I have some questions regarding the power supply configuration. From the official datasheet, I understand the OpenRB-150 has three power supply options. When the jumper is set to VIN(DXL), supplying 11.1V to the Terminal VIN powers both the OpenRB-150 board and the connected MX-28 motors through the board’s DYNAMIXEL ports. However, I have encountered information (in previous posts/discussions) suggestin…

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Assuming that your robot is composed of 4 groups of 3 XL-430s each, then I am suggesting the following configuration:

You probably already have all the hardware needed, except for the X3P Hub. This item is hard to purchase nowadays. But the X4P Hub is available now at ROBOTIS USA Shop.

4P JST Expansion Board

And you can plug X3P cables into an X4P Hub, just make sure to align up properly the X3P connectors for your own use (basically you do not use the 4th pin of the X4P Hub )

The wiring scheme shown above offers the following features:

1. The POWER Circuit for each Servo Group is isolated from the other POWER Circuits of the remaining 3 Servo Groups. But they do share the COMMON GROUND.
2. The CONTROL Circuit via U2D2 and the X3P Hub is isolated from ALL Power Circuits. But the U2D2 does share the COMMON GROUND and ALL TTL DATA Lines so that the U2D2 can control all 12 XL-430s “as normal” and “in parallel”. On the physical robot, try to put the U2D2 and X3P Hub at the “physical center” of the 4 Servo Groups as much as possible.
3. So all the X3P cables are used “as normal”, except for the X3P cables that connect the X3P Hub to the LAST Servo of each of the 4 Daisy Chains: they need to have their VDD wires CUT OFF.