MC_AxisSetDefaults

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Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Sets the default kinematic parameters for an axis.

Inputs

Input	Data Type	Range	Unit	Default	Description
Execute	BOOL	0, 1	N/A	No default	On the rising edge The transition of a digital signal from low to high. AKA: positive edge., request to set the default kinematic parameters.
Axis	AXIS_REF	No range	N/A	No default	Reference to the axis which has its default kinematic parameters set.
Velocity For a group of axes this means: In ACS the velocities of the different axes. In MCS and PCS it provides the velocity of the TCP	LREAL	0 < Velocity < (20 * Acceleration A change in velocity over time. Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. In one dimension, acceleration is the rate at which something speeds up or slows down. However, more generally, acceleration is a vector quantity expressing the change with time of the velocity both in magnitude and in direction. See these Wikipedia articles for more information: http://en.wikipedia.org/wiki/Velocity http://en.wikipedia.org/wiki/Euclidean_vector http://en.wikipedia.org/wiki/Rate_(mathematics)) and 0 < Velocity < (20 * Deceleration)	User unit/sec	No default	The default velocity. See Limitations on Acceleration and Jerk.
Acceleration	LREAL	(Velocity / 20) < Acceleration < (2 * Jerk)	User unit/sec²	No default	Trapezoidal: Acceleration rate. S-curve: Maximum acceleration. See S-curve and Trapezoidal Acceleration / Deceleration. See Function Block Acceleration and Jerk Parameters. See Limitations on Acceleration and Jerk.
Deceleration	LREAL	(Velocity / 20) < Deceleration < (2 * Jerk)	User unit/sec²	No default	Trapezoidal: Deceleration rate. S-curve: Unused. See S-curve and Trapezoidal Acceleration / Deceleration.
Jerk	LREAL	(Velocity / 20) < Acceleration < (2 * Jerk) and (Velocity / 20) < Deceleration < (2 * Jerk)	User unit/sec³	No default	Trapezoidal: 0 (zero). S-curve: Constant jerk. The Jerk value is ignored for motion. Only trapezoidal motion is supported. See S-curve and Trapezoidal Acceleration / Deceleration. See Function Block Acceleration and Jerk Parameters.

Outputs

Output	Data Type	Range	Unit	Description
Done	BOOL	FALSE, TRUE	N/A	If TRUE, the command completed successfully.
Error	BOOL	FALSE, TRUE	N/A	If TRUE, an error has occurred.
ErrorID	DINT	-2147483648 to 2147483647	N/A	Indicates the error if Error output is TRUE. See PLCopen Function Block ErrorIDs.

Output

Data Type

Range

Unit

Description

Done

BOOL

FALSE, TRUE

N/A

If TRUE, the command completed successfully.

Error

BOOL

FALSE, TRUE

N/A

If TRUE, an error has occurred.

ErrorID

DINT

-2147483648 to 2147483647

N/A

Indicates the error if Error output is TRUE.

See PLCopen Function Block ErrorIDs.

Remarks

This function block starts a motion-related action and stores data for calculations and error checking.
See Call Function Blocks Multiple Times in the Same Cycle if using a dual-core controller.

See Coordinated Motion, the top-level topic for Coordinated Motion.
The MC_AxisSetDefaults function block sets the default kinematic variables for MC_MoveDirAbs and MC_MoveDirRel.
- These variables are only used with the MC_MoveDir function blocks.
Each axis in the group must have the default kinematic parameters of Velocity, Acceleration, Deceleration, and Jerk set to values greater than 0 (zero).
- A non-zero Jerk value performs an S-Curve instead of a trapezoidal move.
- Each axis in the group must have these values set before a direct The orientation components of a vector in space. move can be started.
The function block returns an error if the group state is not GroupStandby or GroupDisabled.

Jerk with a non-zero value is currently not supported for coordinated motion.
Jerk parameters are ignored.

Figure 1: MC_AxisSetDefaults

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_AxisSetDefaults( TRUE, CoordAxis1_Ref, default_velocity, default_acceleration, default_deceleration, default_jerk)
END_IL

ST Language Example

 (* ST Structured text - A high-level language that is block structured and syntactically resembles Pascal. MC_AxisSetDefaults Example *)

default_velocity       := 50.0; 
default_acceleration   := 250.0;
default_deceleration   := 300.0;
default_jerk           := 1000.0;

Inst_MC_AxisSetDefaults ( TRUE, CoordAxis1_ref, default_velocity, default_acceleration, default_deceleration, default_jerk);