Real-Time Data Exchange (RTDE) Guide
Introduction
The Real-Time Data Exchange (RTDE) interface provides a way to synchronize external applications with the UR controller over a standard TCP/IP connection, without breaking any real-time properties of the UR controller. This functionality is useful for interacting with fieldbus drivers (e.g., Ethernet/IP), manipulating robot I/O, and plotting robot status (e.g., robot trajectories). The RTDE interface is by default available when the UR controller is running.
The synchronization is configurable and can involve the following data:
Output: robot-, joint-, tool- and safety status, analog and digital I/O’s, and general-purpose output registers.
Input: digital and analog outputs and general-purpose input registers.
The RTDE functionality is split into two stages: a setup procedure and a synchronization loop. On connection to the RTDE interface, the client sets up the variables to be synchronized. The client sends a setup list of named input and output fields to be included in the data synchronization packages. This list is known as a recipe. Each successfully configured input recipe receives a unique recipe ID. Supported field names and their associated data types are listed below.
When the synchronization loop starts, the RTDE interface sends the requested data to the client in the specified order. The client sends updated inputs to the RTDE interface when values change. Data synchronization uses serialized binary data. Packages share a general structure with a header and a payload, if applicable.
Key Features
Real-time synchronization: The RTDE typically generates output messages at 125 Hz. However, if the controller lacks computational resources, it will skip some output packages and only send the most recent data.
Input messages: Variables in the controller can be updated via multiple messages. Inputs retain their last received value, and only one RTDE client can control a specific variable at any time.
Runtime environment: An RTDE client can run on the UR Control Box PC or any external PC. Running the RTDE client on the Control Box avoids network latency but may compete with the UR controller for resources.
Protocol changes: The RTDE protocol may be updated by UR. RTDE clients can request specific protocol versions to ensure compatibility.
Field Names and Associated Types
Robot Controller Inputs
Name |
Type |
Comment |
Introduced in Version |
|---|---|---|---|
speed_slider_mask |
UINT32 |
0 = don’t change speed slider, 1 = use speed_slider_fraction to set speed slider value |
|
speed_slider_fraction |
DOUBLE |
New speed slider value |
|
standard_digital_output_mask |
UINT8 |
Standard digital output bit mask |
|
configurable_digital_output_mask |
UINT8 |
Configurable digital output bit mask |
|
standard_digital_output |
UINT8 |
Standard digital outputs |
|
configurable_digital_output |
UINT8 |
Configurable digital outputs |
|
standard_analog_output_mask |
UINT8 |
Standard analog output mask (Bits 0-1: standard_analog_output_0 | standard_analog_output_1) |
|
standard_analog_output_type |
UINT8 |
Output domain {0=current[mA], 1=voltage[V]} (Bits 0-1: standard_analog_output_0 | standard_analog_output_1) |
|
standard_analog_output_0 |
DOUBLE |
Standard analog output 0 (ratio) [0..1] |
|
standard_analog_output_1 |
DOUBLE |
Standard analog output 1 (ratio) [0..1] |
|
input_bit_registers0_to_31 |
UINT32 |
General purpose bits reserved for FieldBus/PLC interface usage |
|
input_bit_registers32_to_63 |
UINT32 |
General purpose bits reserved for FieldBus/PLC interface usage |
|
input_bit_register_X |
BOOL |
64 general purpose bits (X: [64..127]) reserved for external RTDE clients |
3.9.0 / 5.3.0 |
input_int_register_X |
INT32 |
48 general purpose integer registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
input_double_register_X |
DOUBLE |
48 general purpose double registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
external_force_torque |
VECTOR6D |
Input external wrench when using ft_rtde_input_enable builtin |
3.3 |
Robot Controller Outputs
Name |
Type |
Comment |
Introduced in Version |
|---|---|---|---|
timestamp |
DOUBLE |
Time elapsed since the controller was started [s] |
|
target_q |
VECTOR6D |
Target joint positions |
|
target_qd |
VECTOR6D |
Target joint velocities |
|
target_qdd |
VECTOR6D |
Target joint accelerations |
|
target_current |
VECTOR6D |
Target joint currents |
|
target_moment |
VECTOR6D |
Target joint moments (torques) |
|
actual_q |
VECTOR6D |
Actual joint positions |
|
actual_qd |
VECTOR6D |
Actual joint velocities |
|
actual_current |
VECTOR6D |
Actual joint currents |
|
joint_control_output |
VECTOR6D |
Joint control currents |
|
actual_TCP_pose |
VECTOR6D |
Actual Cartesian coordinates of the tool: (x,y,z,rx,ry,rz) |
|
actual_TCP_speed |
VECTOR6D |
Actual speed of the tool in Cartesian coordinates |
|
actual_TCP_force |
VECTOR6D |
Generalized forces in the TCP |
|
target_TCP_pose |
VECTOR6D |
Target Cartesian coordinates of the tool: (x,y,z,rx,ry,rz) |
|
target_TCP_speed |
VECTOR6D |
Target speed of the tool in Cartesian coordinates |
|
actual_digital_input_bits |
UINT64 |
Current state of the digital inputs (0-7: Standard, 8-15: Configurable, 16-17: Tool) |
|
joint_temperatures |
VECTOR6D |
Temperature of each joint in degrees Celsius |
|
actual_execution_time |
DOUBLE |
Controller real-time thread execution time |
|
robot_mode |
INT32 |
Robot mode |
|
joint_mode |
VECTOR6INT32 |
Joint control modes |
|
safety_mode |
INT32 |
Safety mode |
|
safety_status |
INT32 |
Safety status |
3.10.0 / 5.4.0 |
actual_tool_accelerometer |
VECTOR3D |
Tool x, y, and z accelerometer values |
|
speed_scaling |
DOUBLE |
Speed scaling of the trajectory limiter |
|
target_speed_fraction |
DOUBLE |
Target speed fraction |
|
actual_momentum |
DOUBLE |
Norm of Cartesian linear momentum |
|
actual_main_voltage |
DOUBLE |
Safety Control Board: Main voltage |
|
actual_robot_voltage |
DOUBLE |
Safety Control Board: Robot voltage (48V) |
|
actual_robot_current |
DOUBLE |
Safety Control Board: Robot current |
|
actual_joint_voltage |
VECTOR6D |
Actual joint voltages |
|
actual_digital_output_bits |
UINT64 |
Current state of the digital outputs (0-7: Standard, 8-15: Configurable, 16-17: Tool) |
|
runtime_state |
UINT32 |
Program state |
|
elbow_position |
VECTOR3D |
Position of robot elbow in Cartesian Base Coordinates |
3.5.0 / 5.0.0 |
elbow_velocity |
VECTOR3D |
Velocity of robot elbow in Cartesian Base Coordinates |
3.5.0 / 5.0.0 |
robot_status_bits |
UINT32 |
Bits 0-3: Is power on, Is program running, Is teach button pressed, Is power button pressed |
|
safety_status_bits |
UINT32 |
Bits 0-10: Is normal mode, Is reduced mode, Is protective stopped, Is recovery mode, Is safeguard stopped, Is system emergency stopped, Is robot emergency stopped, Is emergency stopped, Is violation, Is fault, Is stopped due to safety |
|
analog_io_types |
UINT32 |
Bits 0-3: analog input 0, analog input 1, analog output 0, analog output 1 {0=current[mA], 1=voltage[V]} |
|
standard_analog_input_0 |
DOUBLE |
Standard analog input 0 |
|
standard_analog_input_1 |
DOUBLE |
Standard analog input 1 |
|
standard_analog_output_0 |
DOUBLE |
Standard analog output 0 |
|
standard_analog_output_1 |
DOUBLE |
Standard analog output 1 |
|
input_bit_registers0_to_31 |
UINT32 |
General purpose bits reserved for FieldBus/PLC interface usage |
|
input_bit_registers32_to_63 |
UINT32 |
General purpose bits reserved for FieldBus/PLC interface usage |
|
input_bit_register_X |
BOOL |
64 general purpose bits (X: [64..127]) reserved for external RTDE clients |
3.9.0 / 5.3.0 |
input_int_register_X |
INT32 |
48 general purpose integer registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
input_double_register_X |
DOUBLE |
48 general purpose double registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
output_bit_registers0_to_31 |
UINT32 |
General purpose bits reserved for FieldBus/PLC interface usage |
|
output_bit_registers32_to_63 |
UINT32 |
General purpose bits reserved for FieldBus/PLC interface usage |
|
output_bit_register_X |
BOOL |
64 general purpose bits (X: [64..127]) reserved for external RTDE clients |
3.9.0 / 5.3.0 |
output_int_register_X |
INT32 |
48 general purpose integer registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
output_double_register_X |
DOUBLE |
48 general purpose double registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
output_bit_registers |
UINT32 |
32 general purpose bits (0-31) reserved for FieldBus/PLC interface usage |
3.4.0 |
output_int_register_X |
INT32 |
48 general purpose integer registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |
output_double_register_X |
DOUBLE |
48 general purpose double registers (X: [0..23] reserved for FieldBus/PLC, [24..47] for external RTDE clients) |
[0..23] 3.4.0 / [24..47] 3.9.0 / 5.3.0 |