# Connection and Initialization

## Constructor

```python
URCtrl(
    robot_ip="10.170.10.56",
    arm_name="Arm",
    instance_name="Ctrl",
    logger=None,
    log_level=None,
    config=None,
)
```

On initialization, `URCtrl` connects SDU Robotics `ur_rtde` RTDEControl, RTDEReceive, and RTDEIO. Dashboard is connected only when enabled in the configuration.

## config

Representative configuration settings are listed below.

| Setting | Meaning |
|---|---|
| `ROBOT_IP` / `UR_IP` | UR controller IP address |
| `ROBOT_VAR_FILE` / `UR_VAR_FILE` | Virtual-variable storage file |
| `UR_USE_DASHBOARD` | Enable DashboardClient |
| `UR_MAX_LINEAR_SPEED` | Maximum linear speed |
| `UR_MAX_LINEAR_ACCELERATION` | Maximum linear acceleration |
| `UR_MAX_JOINT_SPEED` | Maximum joint speed |
| `UR_MAX_JOINT_ACCELERATION` | Maximum joint acceleration |
| `UR_DEFAULT_BLEND_RADIUS` | Blend radius for `@P` |
| `UR_ALLOW_RESTART_SAFETY` | Allow safety restart |

## Dashboard

`turn_on_motor()`, `turn_off_motor()`, and some `reset_error()` operations require Dashboard.

```python
class Config:
    ROBOT_IP = "10.170.10.56"
    UR_USE_DASHBOARD = True

robot = URCtrl(config=Config)
```

Without Dashboard, these operations return `False` and record the reason in the error information.

## connect()

```python
robot.connect()
```

Connect SDU Robotics `ur_rtde` `RTDEControlInterface`, `RTDEReceiveInterface`, and `RTDEIOInterface`.

## disconnect()

```python
robot.disconnect()
```

Save virtual variables, then disconnect Dashboard, RTDEIO, RTDEReceive, and RTDEControl in that order.

## Context Manager (`with`)

```python
with URCtrl(ROBOT_IP) as robot:
    ...
```

Using `with` calls `disconnect()` when leaving the context.