MC_MoveAbsolute

Movement of the axis to an absolute position is commanded with the FB MC_MoveAbsolute FB. The motion is always executed jerk-limited with the constant set input ‘Jerk’. This value is valid for both ‘acceleration’ and ‘deceleration’.

Block diagram

Parameters of the FB

VAR_IN_OUT
	Axis	AXIS_REF	Axis reference.
VAR_INPUT
	Execute	BOOL	Start the motion at rising edge.
	Position	LREAL	Target position for the motion. Range [-2147483648.0, 2147483647.0] Default unit [0,1µm or 10^-4 °]
	Velocity	LREAL	Value of the maximum velocity (always positive, not necessarily reached). Range [1.0, 2147483647.0] Default unit [1µm/s or 10^-3 °/s]
	Acceleration	LREAL	Value of the acceleration (always positive, increasing energy of the motor). Range [1.0, 2147483647.0] Default unit [1mm/s² or 1°/s²]
	Deceleration	LREAL	Value of the decceleration (always positive, decreasing energy of the motor). Range [1.0, 2147483647.0] Default unit [1mm/s² or 1°/s²]
	Jerk	LREAL	Value of the Jerk (always positive). Range [1.0, 2147483647.0] Default unit [1m/s³ or 1000°/s³]
	Direction	INT	Direction in which the movement is started: 1 positive direction 2 shortest way 3 negative direction 4 current direction Note: Specifying the direction is effective only if a modulo coordinate system has been defined for the axis in the axis-specific machine data, using parameter kenngr.achs_mode.
VAR_OUTPUT
	Done	BOOL	The axis is within a range close to the target position. The range is specified by the parameter getriebe[...].window of the axis-specific machine data.
	CommandAborted	BOOL	Command is aborted by another command.
	Error	BOOL	Indicates if an error has occurred.
	ErrorID	WORD	Error identification.

Behavior of the FB

This motion is commanded only when the axis is in the ‘Standstill’ or ‘Continuous Motion’ or ‘Discrete Motion’ or ‘Synchronized Motion’ state. If this is not the case, the ‘Error’ output is set to FALSE and ‘ErrorID’ indicates an error value that designates the state the axis is currently in.
Within the FB, the ‘position’, ‘velocity’, ‘acceleration’, ‘deceleration’ and ‘jerk’ input variables are monitored only for their value range. If they are exceeded, an error number referring to the variable is output at the ‘ErrorID’ output and ‘Error’ is set to TRUE. Moreover, the maximum speed and acceleration data is limited within the motion controller. If speed values more than getriebe[0].dynamik.vb_max or ‘acceleration’ or ‘deceleration’ values more than getriebe[0].dynamik.a_max are commanded, the motion is nevertheless carried out, but the values are limited to the defined values and the motion controller issues a warning 60211 or 60188 to 60194.
Values that correspond to a minimum ramp time of T_A (cycle time of the IPO, e.g. 2 ms) and a maximum ramp time of 100s make sense as the ‘jerk’. The limit transition to non-jerk-limited speed realization lies at the minimum ramp time of T_A. In the case of a value of 0, the maximum ramp time from the axis MDS is used to determine the ‘jerk’.
With this function block, active commands can be replaced with new commands and so the function block is retriggerable. The active command is thus aborted.
If an axis not referenced is commended by this FB, the axis does not start to move. The error code 60142 is reported on the ‘MC_ReadAxisError’ function block.
The positions of the software limit switches (kenngr.swe_pos, kenngr.swe_neg, kenngr.swe_toleranz) are monitored if the axis has been defined either as a linear or a rotary axis. This means that the kenngr.achs_typ of the axis machine data has the value 0x0001 or 0x0002. If the target position exceeds the position of the software limit switches because of commanding, the axis nevertheless starts off. If a software limit switch position is reached, the axis is braked, keeping to the defined acceleration.