IF_MoveSyncFromStandstill - StartSyncToCarrierBehind (Method)

Overview

Type:	Method
Available as of:	V1.0.0.0

Task

Synchronization of the selected carrier to the carrier behind.

(For more information on the carrier positions, refer to the general description of a Lexium™ MC multi carrier track.)

Description

The method StartSyncToCarrierBehind allows a one-to-one synchronization of the selected carrier to the carrier behind. The carrier behind is considered as the master carrier and the selected carrier is considered as the connected carrier. If the carrier behind is already following a master carrier, then this master carrier is used as the reference.

NOTE: When executing this move command, you override previous move commands.

NOTE: If the carrier behind is already following the selected carrier, it is not allowed to use the method StartSyncToCarrierBehind.

NOTE: When you synchronize more than one carrier to a master using the method StartSyncToCarrierBehind, avoid cascading synchronized carriers: Call the carriers to be synchronized in an order starting with the first carrier next to the master. For more information on synchronizing more than one carrier, refer to the Synchronization examples in the description of the method StartSyncToCarrierInFront.

In synchronized movements of a carrier connected to an external master or to a master carrier in front or behind, the movement of the selected carrier is controlled by the master.

CAUTION
	CARRIER Collision Define the master movement in a way that avoids collisions with other carriers. Failure to follow these instructions can result in injury or equipment damage.

NOTE: You can use the function block FB_CrashPrevention as an additional protection measure to help avoid collisions.

With an open track, the carriers could leave the track at the ends. Therefore, mechanical hard stops must be mounted at both ends of an open track.

WARNING
	EQUIPMENT OPERATION HAZARD Mount mechanical hard stops at both ends of an open track. Failure to follow these instructions can result in death, serious injury, or equipment damage.

As a precondition for calling the method StartSyncToCarrierBehind, both carriers must be in standstill. The value of the parameter Carrier.RefVelocity must be 0. For more information on the carrier object Lexium MC Carrier and the parameter RefVelocity within the user function MovementData, refer to the Lexium™ MC multi carrier Device Objects and Parameters Guide.

The selected carrier follows the carrier behind on the path position with a one-to-one cam according to the following rules:

For the distance between the carriers, the length on the outer side of the guide rails of the track is considered.
The distance between the carrier positions always stays the same.
In the curves, the distance used is the arc length of the curve, measured in mm.

With the synchronized movement, the carrier follows the carrier behind one-to-one without considering the motion parameters specified in the method SetMotionParameter.

Synchronization to carrier behind

Feedbacks

Feedbacks are available in the interface IF_CarrierFeedbackMoveSyncFromStandstill.

Inputs

The method has no inputs.

Outputs

Output	Data type	Description
q_xError	BOOL	Indicates TRUE if an error has been detected. For details, refer to q_etResult and q_sResultMsg.
q_etResult	ET_Result	Provides diagnostic and status information as a numeric value. If q_xError = FALSE, q_etResult provides status information. If q_xError = TRUE, q_etResult provides diagnostic/error information.
q_sResultMsg	STRING [255]	Provides additional diagnostic and status information as a text message.

Call Example

Before executing the method StartSyncToCarrierBehind, the method SetMotionParameter must be called at least once.

Example:

...ifMotion.SetMotionParameter(...)
...ifMoveDirectly.Start(...)
...ifMoveSyncFromStandstill.StartSyncToCarrierBehind(...)