# Chapter 2: Installation and Connection Setup

## About This Chapter

This chapter describes how to connect a PC to a UR robot and configure the system so that Python can communicate with the robot.

After completing this chapter, you should be able to:

- Communicate with the robot
- Configure Remote Control
- Verify connectivity from Python

---

# 2.1 System Configuration

This documentation combines Universal Robots' official communication interfaces with the third-party open-source SDU Robotics `ur_rtde` library. The assumed configuration is:

```
+--------------------+
|      Python PC     |
|                    |
|  ur_ctrl.py        |
|  ur_rtde           |
+---------+----------+
          |
      Ethernet
          |
+---------+----------+
|      UR Robot      |
|                    |
|  Control Box       |
|  Teach Pendant     |
+--------------------+
```

Connect the PC and robot with an Ethernet cable. A network switch may also be used.

---

# 2.2 Required Software

Python 3.10 or later is recommended.

For PC-side motion control, state acquisition, and I/O, this documentation uses SDU Robotics `ur_rtde`. Although it is not an official Universal Robots SDK, it communicates using the official Universal Robots RTDE protocol.

Install the required library:

```bash
pip install ur_rtde
```

The following interfaces are used:

- `RTDEControlInterface`
- `RTDEReceiveInterface`
- `RTDEIOInterface`

---

# 2.3 Installation by Operating System

## Windows

Installation is generally straightforward:

```bash
pip install ur_rtde
```

The Visual C++ Runtime may be required.

---

## Ubuntu

On Ubuntu, dependencies such as Boost may be necessary. For example:

```bash
sudo apt install \
    build-essential \
    cmake \
    libboost-all-dev
```

Then run:

```bash
pip install ur_rtde
```

---

## macOS

Use Homebrew:

```bash
brew install cmake
brew install boost
```

If necessary, configure the environment:

```bash
export PATH=/opt/homebrew/bin:$PATH
```

Depending on the environment, a source build may be required. Note that library paths differ between Intel Macs and Apple Silicon Macs.

---

# 2.4 Robot IP Address

On the Teach Pendant, open:

```
Settings
    ↓
System
    ↓
Network
```

Check the IP address, for example:

```
192.168.0.10
```

Configure the PC on the same subnet. For example:

```
Robot

192.168.0.10

PC

192.168.0.100
```

The subnet mask is usually:

```
255.255.255.0
```

---

# 2.5 Verifying Network Connectivity

First, verify that the robot responds to ping.

Linux/macOS:

```bash
ping 192.168.0.10
```

Windows:

```cmd
ping 192.168.0.10
```

If a response is received, basic network connectivity is working.

---

# 2.6 What Is Remote Control?

To send motion commands from Python, **Remote Control** must be enabled.

If it is not enabled, the following error may occur:

```
Please enable remote control on the robot!
```

This is one of the most common errors returned by `ur_rtde`.

---

# 2.7 Enabling Remote Control

On e-Series robots, enable Remote Control under:

```
Settings
    ↓
System
    ↓
Remote Control
```

Then switch the robot to Remote Mode. External control is unavailable in Local Mode.

---

# 2.8 Remote Mode

The upper-right corner of the Teach Pendant displays either:

```
Local
```

or:

```
Remote
```

For Python-based control, it must display:

```
Remote
```

---

# 2.9 Connecting from Python

A minimal example is:

```python
from rtde_control import RTDEControlInterface

ROBOT_IP = "192.168.0.10"

rtde = RTDEControlInterface(ROBOT_IP)

print("Connected")
```

If no exception occurs, the connection has succeeded.

---

# 2.10 Receive Interface

Robot state is obtained through a separate interface:

```python
from rtde_receive import RTDEReceiveInterface

rtde_r = RTDEReceiveInterface(ROBOT_IP)

print(rtde_r.getActualQ())
```

If joint angles are returned, the interface is working.

---

# 2.11 IO Interface

Use the following interface to control digital I/O:

```python
from rtde_io import RTDEIOInterface

rtde_io = RTDEIOInterface(ROBOT_IP)
```

---

# 2.12 Common Errors

## Please enable remote control on the robot!

Remote Control is disabled.

---

## Connection refused

The IP address is incorrect, or the network configuration does not match.

---

## Robot is not running

The robot is not powered on or running. This may also occur when Emergency Stop is active.

---

## Protective Stop

A safety stop is active. Clear it using the Teach Pendant. If necessary, execute Unlock Protective Stop through the Dashboard Server.

---

# 2.13 Connection Checklist

If the connection fails, check the following:

- [ ] Ethernet cable
- [ ] Ping response
- [ ] IP address
- [ ] Firewall
- [ ] Remote Control
- [ ] Remote Mode
- [ ] Robot Power ON
- [ ] Brake Release completed
- [ ] Emergency Stop cleared
- [ ] Protective Stop cleared

Checking these items in order helps isolate many common problems.

---

# Next Chapter

The next chapter explains the following in detail:

- How RTDE works
- RTDEControl
- RTDEReceive
- RTDEIO