Part 4 of the PLCopen suite of specifications is focused to the coordinated multi-axes motion in 3D space.
Part 1 and Part 2 of the PLCopen Motion Control suite deal with master / slave motion control, a type of coordinated motion control where the master axis position is used to generate one or more slave axis position commands. For three dimensional movements, Motion Control Part 4 goes beyond this using a grouping of a set of axes, without a master axis. In order to work in 3D there are several coordinate systems, as well as a kinematic model of the mechanics involved. The coordinated systems include the axes coordinate system, the machine coordinate system and the product related system.
Current Master/Slave axes methods have the problem that if an error occurs, the other axes have no knowledge about this, and continue their movement. By combining axes in a group it is known upfront which axes are involved and is the basis for better error behavior. PLCopen Motion Control Function Blocks are specified at the user level: the PLC programmer quickly recognizes the behavior of the function block and what happens if it is activated or connected to other blocks in a sequence of motion commands. In the past path oriented movements are programmed either with specific robot oriented programming languages, or “G-code” (for instance cf. DIN 66025) as used in the CNC world. Both consist of a relative small number of users. But without a doubt, the movements which can be described in these languages are applicable to a broader range of applications. This PLCopen initiative transforms the functions known in the CNC and Robotic world for use in PLC applications.
PLCopen Motion Control Part 4 - Coordinated Motion adds this functionality to the PLCopen Motion Control specifications.
About PLCopen
PLCopen was founded in 1992 as an independent worldwide association for industrial suppliers and users. It is the leading association resolving topics related to industrial control programming. PLCopen creates concepts to reduce the costs of industrial automation. These cost savings are realized in areas such as engineering, training, operation and maintenance. Together with its members, PLC open creates specifications to materialize these concepts.
