PLCopen has opened a public review period for an updated version of its Motion Control Part 4 specification, which focuses on coordinated motion and robot control. The draft, labelled version 2.0 – Release for Comments, reflects work within the organisation’s Robotics Workgroup to align the document with the Standard Robot Command Interface developed within Profinet International. According to PLCopen, the update is intended to provide a common approach for controlling multi-axis robotic systems from programmable logic controllers and to support both integrated architectures and remote robot controllers.
The new draft incorporates function blocks and data structures originating from the SRCI while keeping the interface and information model unchanged. This approach is intended to simplify adoption for robot manufacturers already supporting the SRCI. PLCopen states that the revised document maintains a condensed format while covering most features required for advanced kinematics and trajectory handling. The update also expands on topics such as position information, trajectory definitions and transition and buffer modes.
The specification builds on earlier releases of PLCopen Motion Control Part 4, introduced in 2008 and later updated through a corrigendum based on feedback from robot suppliers. The current draft merges the PLCopen work with developments from the SRCI community, which published version 1.3 of its interface in 2022. PLCopen states that the resulting document is network-agnostic and is designed to offer a programming interface that abstracts differences between robot controller implementations.
Path-oriented movements can be programmed through robot-specific languages or formats such as G-code, and PLCopen positions its Motion Control suite as a way to bring these concepts into PLC programming environments. The updated Part 4 extends the Motion Control function blocks defined in Part 1 with features required for coordinated motion in three-dimensional space, including a kinematic model that links mechanical axes to endpoint movement.
