MC_CamIn

 Function Block - Performs a slave axis move which follows the master axis based on the Cam Table specified by CamTableID.

Inputs

Input	Data Type	Range	Unit	Default	Description
Execute	BOOL	0, 1	N/A	No default	On the rising edge, request to queue the move.
Master	AXIS_REF	1 to 256	N/A	No default	Name of a declared instance of the AXIS_REF library function. See Axis Name and Number. See AXIS_REF Structure.
Slave	AXIS_REF	1 to 256	N/A	No default	AXIS_REF.AXIS_NUM is the slave axis number. See AXIS_REF Structure.
MasterOffset	LREAL	No range	User units	No default	Master axis offset. This input is not used if the StartMode input is set to 1 for Resume Mode.
SlaveOffset	LREAL	No range	User units	No default	Slave axis offset. This input is not used if the StartMode input is set to 1 for Resume Mode.
MasterScaling	LREAL	No range	User units	No default	Master axis scale factor. This input is not used if the StartMode input is set to 1 for Resume Mode. Scaling must be a positive value greater than 0 (zero).
SlaveScaling	LREAL	No range	User units	No default	Slave axis scale factor. This input is not used if the StartMode input is set to 1 for Resume Mode. Scaling must be a positive value greater than 0 (zero).
StartMode	INT	0, 1	N/A	No default	Starting mode of the cam profile. The function block uses values that were in effect during the most recently programmed MC_CamIn move for the slave axis. 0 = Start Mode Input indicates if the axis should start a MC_CamIn move as an initial cam start. 1 = Resume Mode Input indicates if the axis should resume the most recently programmed MC_CamIn move. The inputs MasterOffset, SlaveOffset, MasterScaling, and SlaveScaling are not used.
CamTableID	INT	No range	N/A	No default	Profile ID number.
BufferMode	SINT	BM_ABORTING BM_BUFFERED	N/A	No default	The Buffer mode for CamIn block. MC_BUFFER_MODE_ABORT is used to abort an existing camming, gearing, point-to-point, or velocities move. MC_BUFFER_MODE_BUFFERED is only used when an endpoint is specified with the previous move. This limits its use to when the previous move is a point-to-point move (MC_MoveAbsolute or MC_MoveRelative). See Buffer Modes for more information.

Outputs

Output	Data Type	Range	Unit	Description
InSync	BOOL	0, 1	N/A	Indicates the slave axis is in sync with the profile.
Busy	BOOL	0, 1	N/A	Indicates this function block is executing.
Active	BOOL	0, 1	N/A	Indicates this move is the Active move.
CommandAborted	BOOL	0, 1	N/A	Indicates the move was aborted.
Error	BOOL	0, 1	N/A	Indicates either: An invalid input was specified. The move was terminated due to an error.
ErrorID	INT	No range	N/A	Indicates the error if the Error output is high. See PLCopen Function Block ErrorIDs.
EndOfProfile	BOOL	0, 1	N/A	Indicates the end of profile has been reached. If the profile is periodic, this output is set to ON for one ladder scan. If the profile is not periodic, the output remains ON while outside the range of the profile. See Periodic or Not Periodic for more information.

Remarks

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

• This function block is used to either:
  • Initiate a new MC_CamIn move.
  • Resume a previously programmed MC_CamIn move.
• See MC_CamStartPos or MC_CamResumePos for more information about positioning the slave axis prior to calling MC_CamIn.
• See Function Blocks - General Rules about how inputs and outputs work.

Abort Camming

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• Ending camming is also possible with other single axis function blocks (e.g., MC_MoveRelative or MC_MoveAbsolute).

There are two options to stop camming after MC_CamIn has been called:

• MC_CamOut continues motion at the instantaneous final actual velocity of the slave axis when it is called.
  • Axis motion continues at that final actual velocity.
• MC_Halt (with buffer mode input = 0) decelerates axis motion to 0 (zero) speed and stop motion.
• The master / slave relationship between the two axes is ended when MC_CamOut or MC_Halt is called.

Figure 1: MC_CamIn

Usage

The slave axis immediately locks on to the Cam Table profile.

• The Master Offset is used to shift the profile along the master axis.
• The Master Scaling defines the range of the profile along the master axis.
• The Slave Offset is used to shift the profile along the Slave axis.
• The Slave Scaling defines the range of the profile along the slave axis.

Periodic or Not Periodic

• If the profile is periodic, when the end of profile is reached, the profile continues at the start of the profile.
  • The EndOfProfile output is ON for 1 ladder scan.
• If the profile is not periodic, when the end of profile is reached, the slave axis stops and remains at the end of the profile until the master axis returns to within the profile range as defined by MasterScaling.
  • The EndOfProfile output remains ON anytime the master axis is outside of the profile range.

Adjustments Computation is Done

When cam is first started, offsets are adjusted if necessary.

• If the master is not absolute, then master offset = master offset + starting position.
• If the slave is not absolute, then slave offset = slave offset + starting position.

At run-time:

• Master position for profile = master position - master offset.
  • Use master position for profile table to obtain slave profile position.
• Slave commanded position = slave profile position + slave offset.

Dynamically Change a Cam Profile

MC_CamIn can be used to dynamically change from one cam profile to another.

Care must be taken when doing this to avoid unexpected motion.

• 
  

• Tips to dynamically change cam profiles:

  • Verify the first cam’s last position and the replacement cam’s first position are the same.
    • Offsets as set byMC_CamTblSelect affect actual cam position.
  • Verify the first cam’s last velocity and the replacement cam’s first velocity do not cause any unexpected motion.
  • Jumps can be eliminated by defining the present cam as Cyclic and defining the replacement cam as an Absolute Master and Slave, as set by the MC_CamTblSelect inputs.
    • This eliminates any possible small error accumulating when the cam is switched.

Examples

These examples use the MC_CamIn Example image showing the cam profile MyProfile:

Example 1

Example 2

Example 3

Figure 2: MC_CamIn Example

Example 1

Example 2

Example 3

FBD Language Example

Not available.

FFLD Language Example

IL Language Example

Not available.

ST Language Example

(* MC_CamIn ST example *)  //Inst_MC_CamIn is an instance of MC_CamIn
Inst_MC_CamIn( CamStartBool, Axis1, Axis2, 0.0, 0.0, 360.0, 360.0, 0, CamTableID, 0 );

See Also

• Call a Function Block
• Differences between Functions and Function Blocks
• MC_CamOut
• MC_CamResumePos
• MC_CamStartPos
• MC_CamTblSelect