For information on the latest version, please have a look at GL013301.
7.2 Access Control Loss
A. Error Case
When attempting to send motion or system commands, you may encounter the following message:
[Error] Access Control Denied
[Info] Another client currently holds control authority
This indicates that your client program cannot obtain robot control authority from the controller.
B. Root Cause Analysis
The Doosan Robot system allows only one active client to have control authority at a time. If another process — such as DART Studio, another API client, or RT monitoring tool — is currently connected, additional clients will be denied access until the control is released.
This issue often occurs when:
DART Studio is left connected in Monitor or Control Mode.
A previous API session did not close properly (e.g., abnormal termination).
Multiple applications are trying to control the same robot simultaneously.
C. Solution
Open DART Studio, check if another connection is active.
Navigate to Settings → API Control Authority.
Click Release Control if another client holds it.
If using multiple devices, ensure only one program connects to the same robot IP.
Restart the controller service to clear stale sessions (if necessary):
sudo systemctl restart dsr-control
In your client code, always release control after use:
Drfl.release_control(); Drfl.close_connection();
Note
Only one API instance can hold authority for motion or I/O control. Monitoring and logging can still be performed by other clients in parallel.