Motion Coordinated Transform with Orientation (MCTO)

Use the Motion Coordinated Transform with Orientation (MCTO) instruction to establish a bidirectional transform that is set up between a Cartesian and a robot system with coordinates that are joint axes of a robot. The XYZ translation coordinates and the RxRyRz orientation coordinates in the fixed angle convention define the Cartesian coordinates. The geometrical configurations of the robots typically have joint axes that are not orthogonal. The coordinate system type, such as Delta, specifies the geometrical configurations.

Available Languages

Ladder Diagram

Function Block

This instruction is not available in function block.

Structured Text

MCTO(CartesianSystem, RobotSystem, MotionControl, WorkFrame, ToolFrame);

Operands

Configuration

The following table provides the operands used to configure the instruction. These operands cannot be changed at runtime.

For further information of configuring coordinate systems refer to the Motion Coordinate System User Manual publication MOTION-UM002.

Affects Math Status Flags

No

Major/Minor Faults

This instruction generates a major fault if an invalid reference or the wrong reference type is provided. A major fault can occur if an uninitialized reference or a reference of incorrect type is passed to Coordinate System operands. See Index Through Arrays for array-indexing faults.

Execution

Ladder Diagram

Structured Text

Data Flow of MCTO instruction between two coordinate systems

Establish the reference frame for the joint coordinate system to ensure the transformations work properly. Refer to the applicable geometry configuration topic for further information on establishing the reference frame for a robot coordinate system.

Once the robot reference frame is established, the robot can be moved to any desired position in joint space when transform is not enabled. When MCTO is initiated for the first time, a forward transform is executed first to set the corresponding Cartesian coordinate positions. Once the MCTO instruction is active, a bidirectional transform link is established, so that if the Cartesian coordinate is commanded to move to a target position in the Cartesian space along a linear path, the robot moves to the Cartesian target coordinates along a linear path. Similarly, if the Robot is commanded to move to a joint coordinate position, the Robot moves to the joint target position along a non-Cartesian path. While MCTO instruction is active, the system maintains the coordinate system related data for Cartesian and Robot coordinate systems.

This diagram illustrates the transformation from a Cartesian coordinate system(X,Y,Z,Rx,Ry,Rz) to a Delta robot geometry with 5 axes (J1J2J3J4J5). The Rx, Ry, and Rz represent orientations around X,Y,Z axes in a positive direction.

Configure an MCTO instruction

The following illustration shows how to configure an MCTO instruction, with the Cartesian coordinate system as the source and the Delta 5 axis geometry as the target. Configure the source and target coordinate systems in the coordinate system dialog box.

Data flow during forward transform when MCTO is active

A forward transform executes when a move executes on joint coordinates of a robot system with an enabled MCTO instruction. During forward transform, the current joint angle positions compute the corresponding Cartesian coordinate positions based on geometry.

Data flow during inverse transform when MCTO is active

When MCTO is active, during inverse transform, the instruction uses the current cartesian positions and geometry configuration to compute the corresponding joint angle positions. MCTO returns an Error 61 when moving both Cartesian and Joint coordinate systems simultaneously.

Fault codes

For the Motion Coordinated Transform with Orientation (MCTO) instruction, an error will occur at runtime if invalid operand values are provided.

Extended Error codes

Extended Error codes help to further define the error message given by the instruction. Their meaning is dependent upon the Error Code with which they are associated.

Example

The following examples activate the transformations between Cartesian coordinate system CS1 and robot coordinate system CS2, which is a Delta 5 axis geometry. In the first example, neither work frame nor tool frame are specified, so Cartesian positions are computed at robot end-of-arm (EOA), with respect to the robot base frame.

Ladder Diagram

When MCTO is active, with a move to Cartesian positions X = 7.361, Y = -4.25, Z = -928.18, Rx = 180, Ry = 30 and Rz = -30, the MCTO computes the corresponding Joint angle as shown in the following diagram.

Consider the same MCTO, with work frame offsets enabled for X = 50, Y = 50 and Rz = 50. Now MCTO will compute the Cartesian positions with respect to the new work frame.

When a move is programmed to the same end position, the corresponding joint positions are as shown in this diagram.

Consider that the MCTO is programmed with tool frame offsets also enabled for Ry = 50 along with the work frame offsets. MCTO now computes the Cartesian positions with respect to the end of the new work frame and tool frame.

This diagram shows the corresponding Joint angle positions after programming a move to the same end position.

For more information on configuring offsets, see Configure Coordinate System Offsets.

Structured Text

MCTO(CS1, CS2, MCTO1, 0, 0);