Allen-Bradley Studio 5000 Logix Emulate User Manual

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Multi-Axis Coordinated Motion Instructions

Chapter 6

Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018 513

Lock Position

Data Type Description Valid Default

Values

IMMEDIATE

REAL or

TAG

Lock Position in Master Driven Mode

The position on the Master Axis where a Slave Coordinate System should start after the move has been initiated on

the Slave Coordinate System when executing in Master Driven Mode. This is an absolute position (plus or minus) on

the Master Axis in Master Axis units. You can specify a Lock Position to delay the start of motion of a Slave

Coordinate System after the motion instruction has been initiated on the Slave Coordinate System.

If an axis in the Slave Coordinate System is already moving and a coordinated move instruction (MCLM, or MCCM)

with a Lock Position is activated on the Coordinate system, then you will receive an MDSC_LOCK_WHILE_MOVING

error for the MCLM or MCCM instruction.

Because Merge is always performed immediately when an instruction is enabled, a merge instruction that starts at

a nonzero velocity with both a Lock Position and a Merge enabled will receive an MDSC_LOCK_WHILE_MOVING

error.

The Lock Direction determines the direction in which the Master Axis must be moving when it crosses the Lock

Position before the Slave Coordinate System locks to the Master Axis.

Note that if there is an unwind value specified on the Master Axis, then the Lock Position must be between 0 and

the unwind value (that is, the Lock Position cannot be more than one unwind.)

This parameter is only used in Master Driven Mode.

Lock Position in Time Driven Mode

There is no Lock Position in Time Driven Mode for a coordinate system. An error will be generated if the Lock

Direction is not NONE and the system is in Time Driven Mode for an MCLM or MCCM.

This parameter is only used in Master Driven Mode.

Axis Lock Behavior

When the Master axis crosses the Master Lock position in the direction as specified by the motion instruction, the

Slave Coordinate System becomes locked to the Master axis. The LockStatus bit is set at this time.

The MCLM and MCCM instructions on the Slave Coordinate System in MDSC mode go IP as soon as they reach the

head of the motion queue. The head of the queue is defined as the move right before the active move.

For the Immediate Forward Only or Immediate Reverse Only Lock Directions, the Slave Coordinate System gets

locked to the Master Axis immediately when the MCLM or MCCM instruction is executed (goes IP). For the Position

Forward Only or Position Reverse Only Lock Directions, the slave gets locked to the Master Axis when the Master

Axis crosses the Master Lock Position in the direction as specified by the motion instruction. In either case, the

LockStatus bit is set when the lock occurs.

Because there is no bi-directional behavior defined, once locked, the Slave Coordinate System follows the Master

only in the specified direction. If the Master reverses direction, then the Slave stops following the Master. Note that

the LockStatus bit remains set until the Master decelerates to zero. It is cleared at the point of reversal of the Master

axis. The Slave does not follow the Master while the Master travels in the reverse direction.

If the Master axis changes directions again, then the axis LockStatus bit is set again when the Slave Coordinate

System crosses the original reversal point, at which time the slave resumes following the Master Axis.

On the Slave Coordinate System the following restrictions apply:

• If a new instruction succeeds the active motion instruction but it is in the opposite direction of its current

direction, then the error MDSC_LOCK_DIR_MASTER_DIR_MISMATCH is generated on the new motion

instruction when it goes IP. The same is true if the new instruction is started via a merge operation.

• A new instruction merged to an active instruction on the Slave Coordinate System must use the Immediate

Forward Only or Immediate Reverse Only Lock Direction. If the new instruction uses the Position Forward Only or

Position Reverse Only Lock Direction, the error MDSC_LOCKDIR_CONFLICT is generated on the new instruction.

• A Lock Position may be used on an instruction that is merging a paused or dwelling motion instruction.

On the Master Axis, no special restrictions apply.

Note that if an instruction with the merge enabled is enqueued, then the whole queue is flushed and the active

move is terminated.

Note that if Master Axis filtering is enabled on the master axis, then the lock position for the Slave Coordinate

System is delayed by the filter; the amount of delay is dependent on the filter bandwidth.

Default = 0.0

Other manuals for Allen-Bradley Studio 5000 Logix Emulate

Programming Manual92 pages

User Manual103 pages

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Allen-Bradley Studio 5000 Logix Emulate Specifications

General

Type	Emulation Software
Supported Platforms	PC
Operating System	Windows
Compatible Controllers	ControlLogix 5570, ControlLogix 5580, CompactLogix 5370, CompactLogix 5480
Integration	Integrated with Studio 5000 environment
Works with Studio 5000 Logix Designer	Yes
Programming Languages	Ladder Logic, Function Block Diagram, Structured Text, Sequential Function Chart
Communication Protocols	EtherNet/IP
Functionality	Controller Emulation
Purpose	Testing and Debugging
Use Case	Program development, testing, training, and troubleshooting without physical PLC hardware