MC_GrpReadActAcc

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 Function Block - Reads the actual acceleration of the group and the axes in the group.

Inputs

Input

Data Type

Range

Unit

Default

Description

Enable

BOOL

FALSE, TRUE

N/A

No default

If TRUE, this function block reads the current actual acceleration of the group and the axes in the group.

AxesGroup

AXES_GROUP_REF

No range

N/A

No default

The axes group the actual acceleration is read from.

CoordSystem

SINT

Enumerated

N/A

No default

The coordinate system used when reading the actual acceleration.

One of these enumeration values:

Value

Description

CS_ACS

Axes Coordinate System

CS_MCS

Machine Coordinate System

CS_PCS

Product Coordinate System

Acceleration

LREAL[ ]

Dimension: The number of axes in the AxesGroup.

No range

User unit/sec2

No default

An array where the acceleration data is written.

  • The length of the array must equal the maximum number of axes allowed in the group.
  • The maximum number of axes is an argument to the MC_CreateAxesGrp function block used to create axes groups.

Outputs

Output

Data Type

Range

Unit

Description

Valid

BOOL

FALSE, TRUE

N/A

If TRUE, the accelerations have been read without error.

Error

BOOL

FALSE, TRUE

N/A

If TRUE, an error has occurred.

ErrorID

INT

Enumerated

N/A

Indicates the error if Error output is TRUE.

See PLCopen Function Block ErrorIDs.

PathAcceleration

LREAL

No range

User unit/sec2

The current measured path acceleration of the group.

This is measured by taking the square root of the sum of the squared accelerations of each axis.

Remarks

  • See Coordinated Motion, the top-level topic for Coordinated Motion.
  • See Function Blocks - General Rules about how inputs and outputs work.
  • The MC_GrpReadActAcc function block fills the array specified by the Acceleration argument with the actual acceleration of the system in the coordinate system specified by the CoordSystem argument.
    • The measured path acceleration is calculated and reported via the PathAcceleration output.
  • This function or function block does not generate any motion.

    • The actual acceleration is smoothed over the last 10 samples.
      This reduces the error in acceleration estimation but introduces a small amount of phase delay in the reported accelerations.
    • Only the ACS coordinate system is supported.
      See Coordinate Systems.

  • There is a one-to-one correspondence between the axes in AxesGroup and the acceleration values in the Acceleration array.
  • If an index in AxesGroup is unassigned, the acceleration value for that array element in the Acceleration array is 0 (zero).
  • If the element does contain an axis, the Acceleration element is filled with the current actual acceleration for that axis.
    • This is an example of how this works:

Figure 1: MC_GrpReadActAcc

FBD Language Example

FFLD Language Example

IL Language Example

Not available.

ST Language Example

Inst_MC_GrpReadActAcc( DoRead, Group, CoordSys, AccList );

See Also