Function BlockMC_MoveRelativePLCopen motion icon

Description

This function block executes a single-axis move for a specified distance to perform incremental motion.

MC_MoveRelative

Figure 7-140: MC_MoveRelative

Time Diagram

The following figure shows the example of the combination of two relative move FunctionClosedA function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. Blocks:

  • The left part of timing diagram illustrates the case if the Second Function BlockClosedA function block groups an algorithm and a set of private data. It has inputs and outputs. is called after the First one. If First reaches the commanded distance 6000 (and the velocity is 0) then the output Done causes the Second FB to move to the distance 10000
  • The right part of the timing diagram illustrates the case if the Second move Function Blocks starts the execution while the First FB is still executing. In this case the First motion is interrupted and aborted by the Test signal during the constant velocity of the First FB. The Second FB adds on the actual position of 3250 the distance 4000 and moves the axis to the resulting position of 7250

MC_MoveRelative: Timing Diagram

Arguments

For more detail on how inputs and outputs work, refer to PLCopen Function Blocks - General Rules

Input

Execute

Description

Requests to queue the move

 

Data type

BOOL

 

Range

0, 1

 

Unit

N/A

 

Default

Axis

Description

Name of a declared instance of the AXIS_REF library function. For more details,About Axis Name and Number

 

Data type

AXIS_REF

 

Range

[1,256]

 

Unit

N/A

 

Default

Distance

Description

Distance

 

Data type

LREAL

 

Range

 

Unit

User unit

 

Default

Velocity

Description

Velocity setpointClosedSetpoint is the target value that an automatic control system, for example PID controller, will aim to reach

 

Data type

LREAL

 

Range

 

Unit

User unit/sec

 

Default

Acceleration

Description

Trapezoidal: Acceleration rate

S-curve: Maximum acceleration

 

Data type

LREAL

 

Range

 

Unit

User unit/sec2

 

Default

Deceleration

Description

Trapezoidal: Deceleration rate

S-curve: Unused

 

Data type

LREAL

 

Range

 

Unit

User unit/sec2

 

Default

JerkClosedIn physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time

Description

Trapezoidal: 0

S-curve: Constant jerkClosedIn physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time

 

Data type

LREAL

 

Range

 

Unit

User unit/sec3

 

Default

BufferMode

Description

0 = abort

1 = buffer

2 = blend to active

3 = blend to next

4 = blend to low velocity

5 = blend to high velocity

See table in Buffer Modes

 

Data type

SINT

 

Range

[0,5]

 

Unit

N/A

 

Default

Output

Done

Description

Indicates the move completed successfully.
The Command Position has reached the endpoint.

 

Data type

BOOL

Busy

Description

High from the moment the Execute input is one-shot to the time the move is ended

 

Data type

BOOL

Active

Description

Indicates this move is the active move

 

Data type

BOOL

CommandAborted

Description

Indicates the move was aborted

 

Data type

BOOL

Error

Description

Indicates an invalid input was specified or the move was terminated due to an error

 

Data type

BOOL

ErrorID

Description

Indicates the error if Error output is set to TRUE

See table in PLCopen Function Block ErrorID Output

 

Data type

INT

Example

Structured Text

(* MC_MoveRelative ST example *)

Inst_MC_MoveRelative( MovRelReq, Axis1, 10.0, 200.0,150.0, 150.0, 0,0 );

MovRelDone := Inst_MC_MoveRelative.Done; //store Done output into user defined variable

See also how this function is used in the Hole punch project here

Ladder Diagram

MC_MoveRelative: LD example

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