Connect to the robot

This page explains how to prepare a Universal Robots cobot for the SDK, and how to connect to it from C# or Python. It applies to CB-Series and e-Series robots with PolyScope, to the robots with PolyScope X, and to URSim.

Interfaces and ports

The SDK uses the standard interfaces of the robot. Each one is enabled in ConnectParameters, and some must also be enabled on the robot.

The Primary Interface can also use the Secondary Interface (30002) and the read only ports (30011, 30012), with PrimaryInterface.Port. The read only ports do not accept URScript.

Prepare the robot

Network

The robot and the PC must be on the same network, with addresses in the same subnet. On PolyScope, the address is set in the menu at the top right, Settings, System, Network.

Before it connects, Connect sends a ping to the robot and stops if the robot does not answer within 500 ms. When a firewall blocks the ping, set PingBeforeConnecting to false.

Services

For security, each interface must be enabled on the robot. On PolyScope, open the menu at the top right, Settings, Security, Services, and enable the interfaces of the table above.

In Settings, Security, General, the inbound connections must not be restricted for the ports that the SDK uses.

Remote control

On e-Series and PolyScope X, the robot accepts commands from the network only in remote control: Dashboard commands that change its state (power, brakes, load, play), URScript sent with the Primary Interface, and REST commands. Reading data does not need it.

Enable the remote control in Settings, System, Remote Control, then switch the robot from Local to Remote with the icon at the top right of PolyScope.

Firewall of the PC

The antivirus or the firewall of the PC can block these ports. If the connection fails, check them first. The XML-RPC and socket servers listen on the PC: allow their ports in the firewall of the PC.

Connect

Connect("192.168.0.1") opens the Primary Interface and the Dashboard Server. To choose the interfaces and their settings, pass a ConnectParameters:

static void Main(string[] args)
{
var robot = new UR();

var parameters = new ConnectParameters("192.168.0.1");

// Enabled by default
parameters.PrimaryInterface.Enable = true;
parameters.Dashboard.Enable = true;

// RTDE: select the data to exchange and the frequency
parameters.Rtde.Enable = true;
parameters.Rtde.Frequency = 500; // Hz
parameters.Rtde.OutputSetup.Add(RtdeOutputData.ActualTcpPose);
parameters.Rtde.OutputSetup.Add(RtdeOutputData.ActualQ);
parameters.Rtde.InputSetup.Add(RtdeInputData.InputIntRegisters, 24);

// Local XML-RPC server, called by the robot program
parameters.XmlRpc.Enable = true;
parameters.XmlRpc.Port = 50000;

// Local socket server, the robot program connects to it
parameters.SocketCommunication.Enable = true;
parameters.SocketCommunication.Port = 50001;

// SSH and SFTP, with the Linux user of the controller
parameters.Ssh.EnableSsh = true;
parameters.Ssh.EnableSftp = true;
parameters.Ssh.Username = "ur";
parameters.Ssh.Password = "easybot";

// Interpreter Mode and REST API (PolyScope X) are disabled by default
parameters.InterpreterMode.Enable = false;
parameters.Rest.Enable = false;

robot.Connect(parameters);

// ...

// Close every service
robot.Disconnect();
}
}

Each interface is also a class that works without UR: PrimaryInterfaceClient, DashboardClient, RtdeClient, RestClient, SftpClient, SshClient, InterpreterModeClient, XmlRpcServer, SocketCommunicationServer. The page of each interface shows it.

Errors

Connect opens the interfaces one after the other. When one fails, it closes the others and throws:

After the connection, the errors of the background threads raise the event InternalErrorOccured, on UR and on each client.

{
var robot = new UR();
try
{
  robot.Connect("192.168.0.1");
}
catch (InvalidLicenseException ex)
{
  // The trial is over or the license key is not valid
  Console.WriteLine(ex.LicenseInfo);
}
catch (ConnectException ex)
{
  // One service did not connect: the other services are closed
  Console.WriteLine($"{ex.Service} of {ex.RobotIp}: {ex.Message}");
}
catch (Exception ex)
{
  // For example, the robot does not answer the ping
  Console.WriteLine(ex.Message);
}

// Errors that happen after the connection, in a background thread
robot.InternalErrorOccured += (sender, e) =>
{
  Console.WriteLine($"{e.Status}: {e.Message}");
};
}
}

Disconnect

Disconnect() closes every interface. Each client also has its own method: robot.Rtde.Disconnect(), robot.Dashboard.Disable()...

Try it in the demo application

Everything on this page can be tried without writing code, in the Connection page of the demo application.

The demo application is open source. The C# source of this page is ConnectControl.cs.

What to read next

• Develop without a robot: install URSim.
• RTDE and Primary Interface: read the state of the robot.
• Licensing: the 30 day trial and the license key.