UR SRCI

Standard Robot Command Interface

Standard Robot Command Interface (SRCI) is a command-based protocol, using PROFINET. It is an open standard developed and maintained by PROFINET International. SRCI defines many commands for basic and advanced use cases. Some are mandatory and some are optional. UR SRCI implements the set of commands known as the “CORE PROFILE” and is built according to version 1.3 of the SRCI standard.

SRCI moves the entire integration of a robotic application to the PLC including the programming of the robot manipulator. With SRCI, functionality for commanding robot motions and providing an interface for robot programming is added on top of all the common functionalities of the PLC such as work cell logic control and safeguarding. This ‘one to rule them all’ philosophy lifts the burden off the shoulders of the integrator of having to master the many ways different robots are integrated. If you are familiar with PLC programming and SRCI you can integrate any robot.

Prerequisites and Usage

To use SRCI with your Universal Robots cobot, specific requirements must be met.

SRCI Controller
UR SRCI URCap
PolyScope 5.15.0 or above

First, you need a PLC with SRCI Controller functionality. Currently, only Siemens provides this functionality, despite SRCI being an open standard. Next, you must install the UR SRCI URCap on your cobot and purchase a license to activate it. For the limited release phase, licenses are available free of charge—contact your local sales representative for more information.

Additionally, the UR SRCI URCap requires PolyScope version 5.15.0 or later. Note that PolyScope X does not currently support SRCI functionality. Finally, SRCI is compatible with all e-Series cobot arms. Read the full list of requirements in the Compatibility subsection.

This is a list of all 29 supported functions, available when using SRCI with the robot.

General Commands

Command	Description
RobotTask	Handles multiple mechanisms that are required for the RI to work. It must be called once per RA
EnableRobot	Enable/Disable robot into RA power state “Enabled”
GroupReset	Resets and acknowledges info, warning and error messages
SetSequence	Set active sequence

Movement Commands

Command	Description
ChangeSpeedOverride	Commands a speed override from the PLC to the RC
GroupContinue	Continues the processing of the currently active sequence (e.g. interrupted movements)
GroupInterrupt	Interrupts the processing of the currently active sequence (e.g. active movements)
GroupStop	Aborts and deletes all active and buffered commands from the sequence buffer of the active sequence
GroupJog	Manually jog the TCP or the robot joints
MoveAxesAbsolute	Commands movement without a specific path (PTP) of the robot arm to an absolute position specified in Joint Position
MoveDirectAbsolute	Commands movement without a specific path (PTP) of the robot arm to an absolute cartesian position
MoveLinearAbsolute	Commands an interpolated linear movement of the robot arm to an absolute cartesian position
ReturnToPrimary	Return to path left during active interrupt

Read Commands

Command	Description
ReadActualPosition	Reads the current position of the TCP relative to the selected or currently used
ReadActualPositionCyclic	Reads the current position of the robot cyclically
ReadFrameData	Gets a user-frame in the workspace of the robot
ReadLoadData	Read the content of selected payload number
ReadRobotSWLimits	Read actual software limits of the axes
ReadToolData	Gets the offset of the tool
ReadRobotDefaultDynamics	Read default values of robot dynamic parameters used by move commands
ReadRobotReferenceDynamics	Read reference values of robot dynamics for path movement

Write Commands

Command	Description
WriteFrameData	Sets a user-frame in the workspace of the robot
WriteLoadData	Change the configuration of the selected payload number
WriteRobotDefaultDynamics	Write default values of robot dynamic parameters used by move commands
WriteRobotReferenceDynamics	Write reference values of robot dynamics for path movement
WriteToolData	Sets the offset of the tool

Internal Commands

Command	Description
ExchangeConfiguration	Reads and writes specific configuration parameters on RC that are required for the RI to work
ReadMessages	Read pending info, warning, and error messages and move them into the user data block “RobotData”
ReadRobotData	Read robot-specific data from the RC

Siemens - UR Setup

Component	Requirement
Siemens PLC	S7-1500(F) and S7-1500S(F), SIMATIC S7-1500(F) - firmware version 2.8 or newer, SIMATIC S7-1500S(F) - firmware version V20.8 or newer
Siemens TIA Portal	Version 16 or higher
Siemens SIMATIC Robot Library	Version 1.0.1 or higher
Siemens SIMATIC Robot Integrator	Sample project including SIMATIC Robot Library
SRCI URCap	One-time purchased license
PolyScope	PolyScope 5.15.0 or higher
Robot Arm	All e-Series or UR20/UR30