Motion Coordinated Shutdown (MCSD)
This information applies to the
CompactLogix
5370, ControlLogix
5570, Compact GuardLogix
5370, GuardLogix
5570, Compact GuardLogix
5380, CompactLogix
5380, CompactLogix
5480, ControlLogix
5580, and GuardLogix
5580 controllers.
IMPORTANT:
Tags used for the motion control attribute of instructions should only be used once. Re-use of the motion control tag in other instructions can cause unintended operation. This may result in damage to equipment or personal injury.
IMPORTANT:
Risk of Velocity and/or End Position Overshoot
If you change move parameters dynamically by any method, that is by changing move dynamics (MCD or MCCD) or by starting a new instruction before the last one has completed, be aware of the risk of velocity and/or end position overshoot.
A Trapezoidal velocity profile can overshoot if maximum deceleration is decreased while the move is decelerating or is close to the deceleration point.
An S-curve velocity profile can overshoot if:
maximum deceleration is decreased while the move is decelerating or close to the deceleration point; or
maximum acceleration jerk is decreased and the axis is accelerating. Keep in mind, however, that jerk can be changed indirectly if it is specified in % of time.
Architecture | Standard | Safety |
|---|---|---|
CompactLogix 5370, ControlLogix 5570, Compact GuardLogix 5370, and GuardLogix 5570 controllers | Yes | No |
Compact GuardLogix 5380, CompactLogix 5380, CompactLogix 5480, ControlLogix 5580, and GuardLogix 5580 controllers | Yes | No |
Available Languages
Ladder Diagram
Function Block
This instruction is not available in function block.
Structured Text
MCSD(CoordinateSystem, MotionControl);
Operands
Ladder Diagram and Structured Text
Operand | Type | Format | Description |
|---|---|---|---|
Coordinate System | COORDINATE_SYSTEM | Tag | Coordinated group of axes. Reference to the coordinated group of axes.For controllers that support the REF_TO Motion data types, the coordinate system operand type can be replaced by the REF_TO_COORDINATE_SYSTEM type. |
Motion Control | MOTION_INSTRUCTION | Tag | Structure used to access instruction status parameters. |
See Structured Text Syntax for more information on the syntax of expressions within structured text.
Coordinate System
The Coordinate System operand specifies the set of motion axes that define the dimensions of a Cartesian coordinate system. For this release the coordinate system supports up to three (3) primary axes. Only the axes configured as primary axes (up to 3) are included in the coordinate velocity calculations.
Motion Control
The following control bits are affected by the MCSD instruction.
Mnemonic | Description |
|---|---|
.EN (Enable) Bit 31 | The Enable bit sets when the rung transitions from false to true. It resets when the rung goes from true to false. |
.DN (Done) Bit 29 | The Done bit sets when the coordinated shutdown is successfully initiated. It resets when the rung transitions from false to true. |
.ER (Error) Bit 28 | The Error bit sets when the coordinated shutdown fails to initiate successfully. It resets when the rung transitions from false to true. |
MCSD is a transitional instruction:
- In relay ladder, toggle the Rung-condition-in from cleared to set each time the instruction should execute.
- In structured text, condition the instruction so that it only executes on a transition. See Structured Text Syntax.
Master Driven Speed Control (MDSC) and the MCSD Instruction
When the coordinate system is shut down:
- The IP bit of the Master Driven Coordinate Control (MDCC) instruction is reset on an axis that is shutdown.
- The AC bit of the MDCC instruction resets when the axis is stopped as it is shutdown.
- The MCSD instruction clears the pending Master Axis for all future coordinate system motion instructions.
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. A major fault can occur if an uninitialized reference or a reference of the incorrect type is passed to the Coordinate System operand. See
Common Attributes
operand-related faults.Execution
Ladder Diagram
Condition/State | Action Taken |
|---|---|
Prescan | The .EN, .DN, .ER, and .IP bits are cleared to false. |
Rung-condition-in is false | The .EN bit is cleared to false if either the .DN or .ER bit is true. |
Rung-condition-in is true | The .EN bit is set to true and the instruction executes. |
Postscan | N/A |
Structured Text
Condition/State | Action Taken |
|---|---|
Prescan | See Prescan in the Ladder Diagram table. |
Normal execution | See Rung-condition-in is false, followed by rung is true in the Ladder Diagram table. |
Postscan | See Postscan in the Ladder Diagram table. |
MCSD Changes to Status Bits
Status bits provide a means for monitoring the progress of the motion instruction. There are three types of Status bits that provide pertinent information. They are: Axis Status bits, Coordinate System Status bits, and Coordinate Motion Status bits. When the MCS instruction initiates, the status bits undergo these changes.
Axis Status Bits
Bit Name | Meaning |
|---|---|
CoordinatedMoveStatus | Cleared |
Coordinate System Status Bits
Bit Name | Meaning |
|---|---|
ShutdownStatus | Sets when MCSD is executed and all associated axes are shutdown. |
ReadyStatus | Cleared after MCSD executes. |
Coordinated Motion Status Bits
Bit Name | Meaning |
|---|---|
AccelStatus | Cleared after MCSD executes. |
DecelStatus | Cleared after MCSD executes. |
ActualPosToleranceStatus | Cleared after MCSD executes. |
CommandPosToleranceStatus | Cleared after MCSD executes. |
StoppingStatus | Cleared after MCSD executes. |
MoveStatus | Cleared after MCSD executes. |
MoveTransitionStatus | Cleared after MCSD executes. |
MovePendingStatus | Cleared after MCSD executes. |
MovePendingQueueFullStatus | Cleared after MCSD executes. |
Examples
Ladder Diagram
Structured Text
MCSD(myMcsdCoordinateSystem,myMcsdMotionControl);
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