MC_TorqueControl (FB)

FUNCTION_BLOCK MC_TorqueControl

This Function Block commands a controlled torque/force/pressure movement and also limits the movement of an axis.

This Function Block continuously exerts a torque or force of the specified magnitude. This magnitude is approached using a defined ramp (‘TorqueRamp’), and the Function Block sets the ‘InTorque’ output if the commanded torque level is reached. This function block is applicable for force and torque. When there is no external load, force is applicable. Positive torque is in the positive direction of velocity.

• The movement is limited by velocity, acceleration / deceleration or by the value of the torque.

• Specific additional tests are outside this function block. For instance, checking on the traveled distance could be done via tracing the actual positions during the action.

Example

The example below shows the typical behavior of an intermediate “resistive” load (see ‘Deceleration’ limit) with some “inertia” (see ‘TorqueRamp’ limit).

This example could be implemented in a function block diagram like:

Note

This function should not be use together with MC_LimitMotion for the same axis. This function block is implemented as wrapper of two blocks MC_LimitMotion and MC_LoadControl

InOut:

Scope	Name	Type	Initial	Comment
Input	Execute	BOOL		Starts the function block at rising edge
	ContinuousUpdate	BOOL		Decide if new input parameters are processed during the movement. This input is checked only when Execute gets TRUE
	Torque	LREAL		[u] = technical unit. Value of the Torque or Force or Pressure. Positive and negative values are allowed
	TorqueRamp	LREAL		[u/s] = technical unit. Absolute value of the input is considered. If TorqueRamp = 0, will result in a jump for load-change, as fast as possible
	Position	LREAL		[u] = technical unit. The position limitation is just activated if Direction is Positive or Negative, and will limit the position if reached in the respective direction
	Velocity	LREAL		[u/s] = technical unit. Absolute value of the maximum velocity. Velocity=0 will switch off the velocity limitation
	Acceleration	LREAL		[u/s°°2] = technical unit. Value of the maximum acceleration (acceleration is applicable with same sign of torque and velocity) Acceleration=0 will switch off the acceleration limitation.
	Deceleration	LREAL		[u/s°°2] = technical unit. Value of the maximum deceleration (deceleration is applicable with opposite signs of torque and velocity) deceleration=0 will switch off the deceleration limitation.
	Jerk	LREAL		Value of the maximum jerk (not used)
	Direction	MC_Direction	Default	Input Load itself is a signed value. “Direction” applies to the movement for, required load to reach with a positive or negative reference or any direction required. DEFAULT: The required load will be reached, no matter what direction movement is required POSITIVE: The required load will be reached just when it is possible to do so with movement in positive direction NEGATIVE: The required load will be reached just when it is possible to do so with movement in negative direction
	BufferMode	MC_BufferMode		Not supported, default mcABORTING used
Output	InTorque	BOOL		Commanded load finally reached, the actual load can be different
	Busy	BOOL		The function block is not finished
	Active	BOOL		Indicates that the function block has control on the axis
	CommandAborted	BOOL		Command is aborted by another command from other PLCopen function block
	Error	BOOL		Signals that error has occurred within function block
	ErrorID	AC500_MotionControl.ERROR_ID		Error identification. For error details refer to enumeration ERROR_ID from AC500_MotionControl library
Inout	Load_Axis	Load_Ref		Reference to axis