MPIMotionType and MEIMotionType

Definition: MPIMotionType

typedef enum {
    MPIMotionTypeINVALID,

    MPIMotionTypePT,
    MPIMotionTypePTF,
    MPIMotionTypePVT,
    MPIMotionTypePVTF,
    MPIMotionTypeSPLINE,
    MPIMotionTypeBESSEL,
    MPIMotionTypeBSPLINE,
    MPIMotionTypeBSPLINE2,

    MPIMotionTypeS_CURVE,
    MPIMotionTypeTRAPEZOIDAL,
    MPIMotionTypeS_CURVE_JERK,

    MPIMotionTypeVELOCITY,
    MPIMotionTypeVELOCITY_JERK,

    MPIMotionTypeCAM_LINEAR,
    MPIMotionTypeCAM_CUBIC,

    MPIMotionTypeMASK  = 0xFF,
} MPIMotionType;

Description

MPIMotionType is an enumeration of motion profile types. It specifies the motion profile to be generated with mpiMotionStart(...) and mpiMotionModify(...). The motion type also defines the trajectory parameters that must be passed to mpiMotionStart(...) and mpiMotionModify(...). For each MPIMotionType and MEIMotionType there is a corresponding element in the MPIMotionParams{...} or MEIMotionParams{...} structure. For example, when MPIMotionTypeS_CURVE is specified, the MPIMotionSCurve{...} structure must be filled in to specify the trajectory for the S-Curve profile.

The motion profile characteristics can be specified by bitwise OR-ing the MPIMotionType with one or more motion attribute masks. The MPIMotionAttrMask and MEIMotionAttrMask enumerations contain the attribute masks. Attribute masks can be used to enable special features or configure the motion profile calculation and execution properties.

Internally, the motion profile is calculated and broken up into smaller trajectory segments called frames. The frames contain position, time, velocity, acceleration, and jerk trajectory information. The controller buffers the frames in its memory and executes them by loading the values into its trajectory calculator. For simple MotionTypes, like VELOCITY, TRAPEZOIDAL, and S_CURVE, the frames are calculated by the controller. For complex, multi-point motions, like PT, PVT, SPLINE, etc. the frames are calculated in the MPI Library. MotionTypes that are calculated in the controller can be modified on-the-fly with mpiMotionModify(...).

The move types, MPIMotionTypeS_CURVE_JERK and MPIMotionTypeVELOCITY_JERK are only available with custom firmware (Option 21). In the custom firmware, the Velocity/Trapezoidal/S-Curve algorithm is replaced with the S-Curve Jerk algorithm. In the standard firmware, the MPIMotionTypeS_CURVE_JERK and MPIMotionTypeVELOCITY_JERK motion types are not supported and if specified, the MPI will return a "profile not supported" error.

Fore details, see S-Curve Jerk Algorithm and Attributes.

Example
Current Position = 2147483638 (2³¹ - 10)
First Position in Point List = 2147483658 ((2³¹ + 10)
or First Position in Point List = -2147483638 ((2³¹ + 10) - 2³²)

From the controller's point of view, both first positions are the same value, but from the MPI's point of view, they are 2³² apart. With the shortest path algorithm, -2147483638 is converted to 2147483658 so that the motion between the current position and the first position is smooth and does not cause excessive acceleration or velocity.

NOTE: The shortest path algorithm only applies to the delta between the current position and the first point in a points list (path motion). It DOES NOT apply to points within the points list.

Definition: MEIMotionType

typedef enum {
    MEIMotionTypeFRAME,
} MEIMotionType;

Description

MEIMotionType is an enumeration of the controller specific motion profile types. See MPIMotionType for details.

See Also

mpiMotionStart | mpiMotionModify | mpiMotionTYPE | MPIMotionParams | MEIMotionParams | MPIMotionAttr | MEIMotionAttr | Streaming Point Motion Type Calculations |
Frame Buffer Management for Streaming Point Motion