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Mover Object

The Mover function block is the heart of the solution. It contains essential functionality, including:

  • Basic administrative commands like enabling & resetting
  • Easily commanding movements to absolute positions or stations
  • Reading out current move status information like position, velocity, etc.
  • Updating motion parameters during operation

Setup & Execution

It is recommended, but not required, to declare Movers as an array. 

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// Instance declaration
Mover           : ARRAY [0..GVL.NUM_MOVERS-1] OF Mover;

ParameterSet    : MoverParameters_typ;

Movers contain a Cyclic() method that must be called every cycle. This cyclic method must also be given a Collision Avoidance Group reference as an argument. If track management is used, the CyclicTrack() method must also be called each scan.

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// Call this method cyclically
FOR i := 0 TO GVL.NUM_MOVERS-1] DO
    Mover[i].Cyclic( GroupRef );
END_FOR

Methods

Enable

Enable()

Carries out steps to prepare the Mover for motion commands.

  1. An internal MC_Reset function block is called to reset any errors that may exist on the Axis object.
  2. The mover will read M1 Detection Settings configured in the XtsProcessingUnit. If M1 Detection is configured, the Mover will activate this process to find Mover 1. If this is not configured, this step is skipped.
  3. An internal MC_Power function block is called to energize the axis object.
  4. The mover will automatically add itself to a Collision Avoidance group, and if necessary will also automatically enable this group.
  5. The mover will set its Ready output True.
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Mover[1].Enable();



Disable

Disable()

Disables the mover. Holding Torque will be lost. Method will automatically remove the mover from its Collision Avoidance group.

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Mover[1].Disable();

GroupStop

GroupStop()

Immediately stops all enabled movers on the system with the deceleration parameters of the mover on which the method was called.

Since the method acts upon the collision avoidance group, all enabled movers on the system are immediately stopped and any active movements are cancelled. New motion commands to each mover are ignored until the Stop has completed.

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IF xStopAllMovers THEN
    Mover[0].GroupStop();
    xStopAllMovers      := FALSE;
END_IF



Halt

Halt()

Immediately stops the commanded mover with the deceleration parameters stored in the Mover object

Halt does not alter the mover's internal axis state, so new movements can be executed at any point to send the mover onwards.

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IF xStopSingleMover THEN
    Mover[0].Halt();
    xStopSingleMover    := FALSE;
END_IF



MoveToPosition

MoveToPosition( Destination : LREAL )

Executes an Absolute Move (with Collision Avoidance) to the target location.

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IF xMoveCommand THEN
    Mover[1].MoveToPosition( 1200 );
    xMoveCommand    := FALSE;
END_IF



MoveToStation

MoveToStation( Destination : Station )

Executes an Absolute Move (with Collision Avoidance) to the location of the target Station, and implicitly calls that Station's RegisterMover method.

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IF xMoveToHome THEN
    Mover[1].MoveToStation( Station[1] );
    xMoveToHome     := FALSE;
END_IF



MoveVelocity

MoveVelocity( DesiredVelocity : LREAL )

Executes a Velocity movement (with Collision Avoidance) at the specified Velocity. This command also implicitly updates the Mover's internal Velocity Motion Parameter.

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IF xMoveVelocity THEN
    Mover[1].MoveVelocity( 2000 );
    xMoveVelocity   := FALSE;
END_IF



SyncToAxis

SyncToAxis( MasterAxis : AXIS_REFERENCE, MasterSyncPos : LREAL, SlaveSyncPos : LREAL, SyncStrategy : MC_SYNC_STRATEGY )

Pairs the current mover with an external axis (real or virtual) with specified Master & Slave Sync Positions. The current mover will synchronize according to the parameter SyncStrategy and a 1:1 gear ratio. The synchronization can be ended by executing a call on the slave for any other motion command, e.g. MoveToPosition.

MasterAxis is a reference to the NC axis object that the mover should synchronize with, real or virtual.

MasterSyncPos is the position of the Master at which point the mover will be InSync and will have the correct gear ratio (1:1).

SlaveSyncPos is the position of the mover at which point it is InSync

SyncStrategy defines the type of calculation used to blend the movements and establish the synchronization. Simply put, the mover should synchronize immediately & aggressively, as late as possible and aggressively, or as gently as possible.

For more information on these inputs, see InfoSys documentation for the underlying MC_GearInPosCA Function Block

See also: Mover.IsSyncedToAxis

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IF xCmdSyncToAxis THEN
    xCmdSyncToAxis  := FALSE;
    MasterSyncPos   := ConveyorAxis.NcToPlc.ActPos + 400;
    Mover[0].SyncToAxis( ConveyorAxis, MasterSyncPos, 1500, mcSyncStrategyEarly );
END_IF;



SyncToMover

SyncToMover( MasterMover : Mover, Gap : LREAL )

Pairs the current mover with a desired mover at a specified gap distance. The current mover will immediately move (with CA) to a specified distance from the Master Mover and then mimic all motion from the master. The synchronization can be ended by executing a call on the slave for any other motion command, e.g. MoveToPosition.

Gap specifies a center-to-center following distance between master and slave movers. This gap cannot be achieved if it is below the minimum collision avoidance distance established in the CA group. Positive Gap values will result in a following position behind the master and negative values will result in a slave that precedes the master.

Additional calls to this method can be used to update the gap between paired movers.

See also: Mover.IsSyncedToMover and Mover.MasterMover

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IF xCmdSyncToLeader THEN
    Mover[0].SyncToMover( Mover[1], 100 );  // move 100mm away from Mover 1

    IF Mover[0].IsSyncedToMover THEN
        Mover[1].MoveToPosition( 2000 );    // Master moves to 2000 and Mover 0 will follow
    END_IF;
END_IF;

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IF xBuildTrain THEN
    Mover[3].SyncToMover( Mover[4], 100 );
    Mover[2].SyncToMover( Mover[4], 200 );
    Mover[1].SyncToMover( Mover[4], 300 );
    Mover[0].SyncToMover( Mover[4], 400 );

    IF Mover[0].IsSyncedToMover THEN
        // Commands Mover 4 to move ahead at 300 mm/s
        Mover[0].MasterMover.MoveVelocity( 300 );
    END_IF;
END_IF;



ReissueCommand

ReissueCommand()

Executes the latest command that was issued to the mover, e.g. a MoveToPosition command. The move is executed with the current internal Motion Parameters of the Mover, so the dynamics of the mover may not exactly match what was initially commanded. However, in cases of MoveToPosition or MoveToStation, the destination will be the same.

To determine what type of movement ReissueCommand() will repeat, see Mover properties CurrentMoveType, CurrentObjective, and CurrentDestinationPosition.

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// Issue a primary command
IF xInitialCommand THEN
    Mover[1].SetVelocity( 500 );
    Mover[1].MoveToPosition( 1000 );
    xInitialCommand     := FALSE;

// Reissue the primary command, but with a new velocity parameter
ELSIF xUpdateCommand THEN
    Mover[1].SetVelocity( 750 );
    Mover[1].ReissueCommand();
    xUpdateCommand      := FALSE;
END_IF



LogUserEvent

LogUserEvent( Text1 : STRING, Text2 : STRING, Text3 : STRING )

Submits custom log events to the Event Logger which can be viewed in TwinCAT

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IF PositionTrigger[1].MoverPassedPosition THEN
    PositionTrigger[1].CurrentMover.LogUserEvent('Mover Passed PT#1','','');
END_IF;



SetAcceleration

SetAcceleration( DesiredAccel : LREAL )

Updates the Mover's internal Motion Parameter for Acceleration [mm/s2] and immediately reissues any currently executing motion blocks so that the parameter update takes effect immediately

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IF xCommandHighAccel THEN
    Mover[1].SetAcceleration( 2e4 );    // mm/s2
    xCommandHighAccel       := FALSE;
END_IF



SetDeceleration

SetDeceleration( DesiredDecel : LREAL )

Updates the Mover's internal Motion Parameter for Deceleration [mm/s2] and immediately reissues any currently executing motion blocks so that the parameter update takes effect immediately

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IF xCommandLowDecel THEN
    Mover[1].SetDeceleration( 1e3 );    // mm/s2
    xCommandLowDecel    := FALSE;
END_IF



SetDirection

SetDirection( Direction : Tc3_Mc3Definitions.MC_Direction );

Updates the Mover's internal Motion Parameter for Direction and immediately reissues any currently executing motion blocks so that the parameter update takes effect immediately

This method should only be used with care, and an understanding that a mover enroute will immediately reverse course and execute a motion command in the opposite direction when this method is called.

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// For supported directions, see Infosys

IF xReverseDirection THEN
    Mover[1].SetDirection( mcDirectionPositive );
    xReverseDirection   := FALSE;
END_IF



SetJerk

SetJerk( Jerk : LREAL )

Updates the Mover's internal Motion Parameter for Jerk [mm/s3] and immediately reissues any currently executing motion blocks so that the parameter update takes effect immediately

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IF xUpdateJerk THEN
    Mover[1].UpdateJerk( 1e5 );
    xUpdateJerk     := FALSE;
END_IF



SetVelocity

SetVelocity( DesiredVelocity : LREAL )

Updates the Mover's internal Motion Parameter for Velocity [mm/s] and immediately reissues any currently executing motion blocks so that the parameter update takes effect immediately

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IF xCommandSlowMode THEN
    Mover[1].SetVelocity( 500 );    // mm/s
    xCommandSlowMode    := FALSE;
END_IF

ActivateTrack

ActivateTrack( DesiredTrack : Track )

Updates the mover's logical track.

This method is used with track management to change the track that the mover is assigned to. Two conditions should be considered when changing tracks. - A mover will stop immediately when ActivateTrack is called. It's recommended to only change tracks when the mover is in a stopped position. - A mover's position can change when calling ActivateTrack. This will happen if the zero point for the current track and new track are different.

A track change takes several PLC and NC scans. Issuing a motion command while this change is in progress will cause the mover to throw an error. To check if the track change is complete monitor the Mover.IsTrackReady property.

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// state machine
100:
    Mover[0].ActivateTrack(Track1);
    IF (Mover[0].IsTrackReady) THEN
        iState := 200;
    END_IF;
200:
    // mover is ready for additional commands

Properties

.CurrentMoveType

MoverCommandType_enum

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MOVETYPE_NONE           // this mover was just enabled and has no movement history
MOVETYPE_POSITION       // this mover was most recently issued a MoveToPosition command
MOVETYPE_STATION        // this mover was most recently issued a MoveToStation command
MOVETYPE_VELOCITY       // this mover was most recently issued a MoveVelocity command

Provides the current (last executed) type of movement command issued to the Mover



.CurrentDestinationPosition

LREAL

Provides the current destination position for the last movement command issued to the Mover. For Station commands, this will be the Position of the Station. For Velocity commands with no real destination position, the value is set to +/-1E300.



.MotionParameters

MotionParameters_typ

Defines a structure containing the dynamics settings for the Mover. Any new motion commands issued will utilize these values.

Note: despite listing this value as a Property here in the documentation, MotionParameters are actually defined as a regular Input to the Mover object. This allows component access to the members of the STRUCT, which is not possible for Properties.



.CurrentObjective

STRING

Provides the current Objective destination for the Mover. Right now this is only valid when the Mover is destined for a Station objective, and provides a string name for that station.



.CurrentTrack

POINTER TO Track

Returns a pointer to the track that this mover is currently assigned to.

Use the ^ operator to dereference the pointer and query track properties

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currentTrackId := Mover[1].CurrentTrack^.Id



.IsSyncedToMover

BOOL

Returns true if the mover is slaved to another mover and has successfully reached the following position specified by the Gap.



.IsSyncedToAxis

BOOL

Returns true if the mover is slaved to an external axis and has successfully reached the following position specified by the Master & Slave Sync Positions



.IsTrackReady

BOOL

Returns true when the ActivateTrack() method has completed successfully. When using track management motion commands should not be issued unless this value is true or the mover will throw an error.



.MasterMover

REFERENCE To Mover

Reference variable that refers to the Mover this Mover is currently slaved to

When this mover is not slaved to another mover, .MasterMover is an invalid reference. There is therefore an ErrorMover object which will return information on what action was requested by the object while .MasterMover was invalid. This will show up in TwinCAT's Event Logs. See Diagnostics / ErrorMovers for more information.

It is recommended that all evaluations are nested inside IF checks for .IsSyncedToMover OR by calling __ISVALIDREF



.Payload

!!! Under Construction !!! At the moment, this property is a placeholder for application specific information regarding the current status of products onboard the mover, and can be modified as needed for your application.



.TrackInfo

Returns information provided by MC_ReadTrackPositions for use with track management.

Member Type Description
TrackId OTCID The hardware ID of the track the mover is assigned to
PartId OTCID The hardware ID of the part the mover is physically present on
TrackPosition LREAL Position of the mover measured from the zero point of the track. This may differ from Mover.AxisReference.NcToPLC.ActPos in certain track configurations
PartPosition LREAL Position of the mover measured from the zero point of the part the mover is physically on



Extra Examples

Below are simple examples of different operations utilizing the Mover object:

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// Mover: ARRAY [0..GVL.NUM_MOVERS] OF Mover
Mover[1].SetVelocity( 2500 );
Mover[1].MoveToPosition( 1200 );