MC_GrpReadCmdPos

PLCopen motion icon Pipe Network motion icon

Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Reads the command position Position means a point in space which is described by different coordinates. Depending on the used system and transformation it can consist of a maximum of six dimensions (coordinates).This means three Cartesian coordinates in space and coordinates for the orientation. In ACS there can be even more than six coordinates. If the same position is described in different coordinate systems the values of the coordinates are different. of the axes in the group.

Inputs

Input	Data Type	Range	Unit	Default	Description
Enable Enable signal for the drive, Hardware-Enable with 24V signal to X8, Software-Enable command by setup Software, fieldbus or permanently set. Both are required for enabling the drive.	BOOL	FALSE, TRUE	N/A	No default	If TRUE, this function A function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. block reads the current commanded position of the axes in the group.
AxesGroup	AXES_GROUP_REF	No range	N/A	No default	The axes group the commanded position is read from.
CoordSystem	SINT	One of these enumeration values: MC_COORDINATE SYSTEM The reference system in which a coordinate or path is described._ACS Axes Coordinate System - The system of coordinates related to the physical motors and the single movements caused by the single drives. = 0 MC_COORDINATE_SYSTEM_MCS = 1 MC_COORDINATE_SYSTEM_PCS Product Coordinate System or Program Coordinate System. The PCS is based on the MCS by shifting and maybe rotating the MCS. The Zero point of the PCS is related to the product and can be changed during runtime by the program. The real work piece can have a rotation or shift to the MCS coordinate system or even might be moving relative to the MCS coordinate system. By specifying a trajectory in PCS one is able to describe the trajectory independent from the machine situation. To map these two worlds (MCS to PCS and vice versa), a Cartesian or cylindrical transformation is normally done. = 2	N/A	No default	The coordinate system used when reading the commanded position.
Position[]	LREAL	No range	User units	No default	An array where the position 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 positions have been read without error.
Error	BOOL	FALSE, TRUE	N/A	If TRUE, an error has occurred.
ErrorID	INT	No range	N/A	Indicates the error if Error output is TRUE. See PLCopen Function Block ErrorIDs.

Output

Data Type

Range

Unit

Description

Valid

BOOL

FALSE, TRUE

N/A

If TRUE, the positions have been read without error.

Error

BOOL

FALSE, TRUE

N/A

If TRUE, an error has occurred.

ErrorID

INT

No range

N/A

Indicates the error if Error output is TRUE.

See PLCopen Function Block ErrorIDs.

Remarks

This function or function block returns cached data.
See Program a Multi-Core Controller.

See Coordinated Motion, the top-level topic for Coordinated Motion.
See Function Blocks - General Rules about how inputs and outputs work.
The MC_GrpReadCmdPos function block fills the array (specified by the Position argument) with the commanded position of the coordinate system specified by the CoordSystem argument.
This function or function block does not generate any motion.

Only the ACS coordinate system is supported.
See Coordinate Systems.

There is a one-to-one correspondence between the axes in the Axes Group and the position values in the Position Array.
Each element in the Position Array corresponds to the axis element in the Axis Group array.
If an index Zero pulse (zero signal) of a hardware pin such as digital input or feedback pin. in the Axes Group is unassigned, the position value for that array element in the Position Array is 0 (zero).
If the element does contain an axis, the position value is filled with the current actual position for that axis.
- This is an example of how this works:

Figure 1: MC_GrpReadCmdPos

FBD Language Example

FFLD Language Example

IL Language Example

            BEGIN_IL Instruction list - This is a low-level language and resembles assembly.
            
     CAL Inst_MC_GrpReadCmdPos( DoRead, Group, CoordSys, PosList )
END_IL

ST Language Example

            (*MC_GrpReadCmdPos ST Structured text - A high-level language that is block structured and syntactically resembles Pascal. example *)
Inst_MC_GrpReadCmdPos(DoRead, Group, CoordSys, PosList );