MC_SetPosition

MC_SetPosition sets the current axis position to a parameterizable value.

In absolute mode, the actual position is set to the parameterized absolute Position value. In relative mode, the actual position is offset by the parameterized Position value. In both cases, the set position of the axis is set such that any following error that may exist is retained. The switch Options.ClearPositionLag can be used to clear the following error.

Relative mode can be used to change the axis position during the motion.

Inputs


VAR_INPUT
    Execute  : BOOL;
    Position : LREAL; 
    Mode     : BOOL; (* RELATIVE=True, ABSOLUTE=False (Default)*)
    Options  : ST_SetPositionOptions; 
END_VAR

Execute	The command is executed with a rising edge at input Execute.
Position	Position value to which the axis position is to be set. In absolute mode the actual position is set to this value, in relative mode it is shifted by this value.
Mode	The axis position is set to an absolute value set if Mode=FALSE. Otherwise is the axis position is changed relative to the specified Position value. Relative mode can be used for changing the position of an axis during motion.
Options	The data structure option includes additional, rarely required parameters. The input can normally remain open.
Options.	ClearPositionLag	ClearPositionLag can optionally be used to set the set and actual positions to the same value. In this case the following error is cancelled.
Options.	SelectEncoderIndex	SelectEncoderIndex can optionally be set if an axis with several encoders is used and the position of a certain encoder is to be set (Options.EncoderIndex).
Options.	EncoderIndex	EncoderIndex indicates the encoder (0 to n) if SelectEncoderIndex is TRUE.

General rules for MC function blocks

Outputs


VAR_OUTPUT
    Done    : BOOL;
    Busy    : BOOL;
    Error   : BOOL;
    ErrorID : UDINT;
END_VAR

Done	The Done output becomes TRUE, once the position was set successfully.
Busy	The Busy output becomes TRUE when the command is started with Execute and remains TRUE as long as the command is processed. If Busy becomes FALSE again, the function block is ready for a new job. At the same time one of the outputs, Done or Error, is set.
Error	Becomes TRUE if an error occurs.
ErrorID	If the error output is set, this parameter supplies the error number

General rules for MC function blocks

Inputs/outputs


VAR_IN_OUT
    Axis    : AXIS_REF;
END_VAR

Axis

Axis data structure

The axis data structure of type AXIS_REF addresses an axis uniquely within the system. Among other parameters it contains the current axis status, including position, velocity or error status.