FastSyncRead Rx Fail

[AnthonyZJiang]

I am setting up openmanipulator-x for ROS2. I have made it working so far with sync read/write, and now trying to solve this fast sync read problem.

I can see in dynamixel wizard that for each servo the indrect addresses have been set correctly:

I can also see the correct values in the corresponding indrect data area. I am using the default baud rate 1 Mpbs.

[ros2_control_node-1] Dynamixel Read Type : sync read
[ros2_control_node-1] ID : 11, 12, 13, 14, 15,
[ros2_control_node-1] Read items :      Present Position        Present Velocity        Present Current
[ros2_control_node-1] set fast sync read (indirect addr) : addr 634, size 10
[ros2_control_node-1] FastSyncRead handler set up successfully.
[ros2_control_node-1] Success to set SyncRead handler using indirect address
[ros2_control_node-1] [INFO] [1756974492.189950793] [dynamixel_hardware_interface]: $$$$$ Init Dxl Write Items
[ros2_control_node-1] Dynamixel Write Type : sync write
[ros2_control_node-1] ID : 11, 12, 13, 14, 15,
[ros2_control_node-1] Write items :     Goal Current
[ros2_control_node-1] set sync write (indirect addr) : addr 224, size 2
[ros2_control_node-1] Success to set SyncWrite handler using indirect address
[ros2_control_node-1] [INFO] [1756974492.204756866] [leader.controller_manager]: Successful initialization of hardware 'OpenManipulatorXSystem'
[ros2_control_node-1] [INFO] [1756974492.205068055] [resource_manager]: 'configure' hardware 'OpenManipulatorXSystem'
[ros2_control_node-1] [INFO] [1756974492.205083056] [resource_manager]: Successful 'configure' of hardware 'OpenManipulatorXSystem'
[ros2_control_node-1] [INFO] [1756974492.205088035] [resource_manager]: 'activate' hardware 'OpenManipulatorXSystem'
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 1/10)
[ros2_control_node-1] [ERROR] [1756974492.240218155] [dynamixel_hardware_interface]: Communication Fail --> SYNC_READ_FAIL
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 2/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 3/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 4/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 5/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 6/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 7/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 8/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 9/10)
[ros2_control_node-1] FastSyncRead Rx Fail [Dxl Size : 5] [Error code : -3001]
[ros2_control_node-1] FastSyncRead TxRx failed (attempt 10/10)
[ros2_control_node-1] FastSyncRead failed 10 times, switching to normal SyncRead permanently.
[ros2_control_node-1] set sync read (indirect addr) : addr 634, size 10

[Woojin-Crive]

Hello @AnthonyZJiang !

Can you let us know which type of Dynamixel are you using and the firmware version of them for OpenMANIPULATOR-X?

The Dynamixel Hardware Interface tries to use 'Fast' Protocols for SyncRead and BulkRead but when there is a Dynamixel does not support Fast protocol, it changes the strategy to use normal SyncRead and BulkRead. And it tries for 10 times to detect it, so the log is written like it. Of course, There is no problem to use normal SyncRead.

Thanks!

[AnthonyZJiang]

Hello @AnthonyZJiang !

Can you let us know which type of Dynamixel are you using and the firmware version of them for OpenMANIPULATOR-X?

The Dynamixel Hardware Interface tries to use 'Fast' Protocols for SyncRead and BulkRead but when there is a Dynamixel does not support Fast protocol, it changes the strategy to use normal SyncRead and BulkRead. And it tries for 10 times to detect it, so the log is written like it. Of course, There is no problem to use normal SyncRead.

Thanks!

Hi,

Thanks for helping. The servos are all XM430-W350-T. I am currently working on another project and will needs sometime to go back and figure out the firmware they are using.

The issue I had seems only occur in Windows subsystem for Linux (Ubuntu 24.04, jazzy). I noticed when I run the same code, using the same parameters, on a native Ubuntu 24.04 machine, the issue disappears.

There are two issues when running WSL Ubuntu:

1. I was not able to enable realtime settings for ROS control on WSL machine. This was not a problem on the native Ubuntu machine.
2. I need to bind and attach the usb device from Windows OS to WSL.

Thanks!

[Woojin-Crive]

Hi @AnthonyZJiang ,

I’m glad to hear that the same code ran well on native Ubuntu 24.04!
It looks like you’re using usbipd to bind a serial port to WSL, but I wouldn’t recommend this approach for controlling a robot.

The code itself doesn’t seem to have any issues, but I’ll keep this issue open for a while to support you further.

Also, we’ve recently opened a new Discord server for ROBOTIS — feel free to join and share your experiences or questions there: https://discord.gg/H6exk2dX

Thanks!