MC_GrpReadActAcc
Description
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 also calculated and reported via the ‘PathAcceleration’ output. This function block does not cause any motion.
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- 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.
- Currently, only the ACS coordinate system is supported. See Coordinate Systems to learn more.
Figure 7-171: MC_GrpReadActAcc
There is a one-to-one correspondence between the axes in the Axes Group array and the acceleration values in the Acceleration array. Each element in the Acceleration array corresponds to the axis element in the Axes Group array. If an index in the Axes Group is unassigned then the acceleration value for that array element in the Acceleration array will be 0. If the element does contain an axis then the acceleration value will be filled with the current actual acceleration for that axis. Here is an example to illustrate how this works:
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This function or function block returns cached data. See Programming a Dual Core Controller for more information.
Related Functions
MC_GrpReadActPos, MC_GrpReadActVel, MC_GrpReadCmdPos, MC_GrpReadCmdVel
Coordinated Motion, the top-level topic for Coordinated Motion.
Arguments
For more detail on how inputs and outputs work, refer to PLCopen Function Blocks - General Rules.
Input
Enable | Description | If True, then this function block will read the current actual acceleration of the group and the axes in the group |
Data type | BOOL | |
Range | 0, 1 | |
Unit | N/A | |
Default | — | |
AxesGroup | Description | The axes group from which the actual acceleration will be read. |
Data type | AXES_GROUP_REF | |
Range | N/A | |
Unit | N/A | |
Default | — | |
CoordSystem | Description | The coordinate system used when reading the actual acceleration |
Data type | SINT | |
Range |
One of the following enumeration values:
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Unit | N/A | |
Default | — | |
Acceleration[] | Description | An array where the acceleration data will be 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 MC_CreateAxesGrp that is used to create axes groups. |
Data type | LREAL | |
Range | N/A | |
Unit | User units per second2 | |
Default | — |
Output
Valid | Description | If true, the accelerations have been read without error. |
Data type | BOOL | |
Error | Description | If true, an error has occurred. |
Data type | BOOL | |
ErrorID | Description | Indicates the error if Error output was set to TRUE. See the table PLCopen Function Block ErrorID Output |
Data type | INT | |
PathAcceleration | Description | The current measured path acceleration of the group, measured by taking the square root of the sum of the squared accelerations of each axis. |
Data type | LREAL | |
Unit | User units per second2 |
Example
Structured Text
Inst_MC_GrpReadActAcc( DoRead, Group, CoordSys, AccList );
IL
BEGIN_IL"Instruction list" This is a low-level language and resembles assembly CAL Inst_MC_GrpReadActAcc( DoRead, Group, CoordSys, AccList ) END_IL
FBD
Ladder Diagram