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SINUMERIK 840D sl. Service - Functions. Manual (2018-2020) - page 24

Kinematic chain

5.2 Commissioning

5.2.3.4

$NK_PARALLEL

Function

The name of the element that branches off before the current element should be entered in the

system variable. The branching element is parallel to the current element. Changes to the

current element, e.g. position changes of the assigned machine axis, have no effect on the

parallel element.

Syntax

$NK_PARALLEL[<n>] = "<name>"

Meaning

$NK_PARALLEL:

Name of the parallel element

Data type:

STRING

Range of values:

All names contained in $NK_NAME (Page 411)

Default value:

"" "" (empty string)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<name>:

Element name, max. string length: 31 characters

Data type:

STRING

Example

The "Offset to the rotary table" element is arranged parallel to the 9th kinematic element:

Program code

Comment

N100 $NK_PARALLEL[8] = "Offset to the rotary

; Parallel to the 9th kin. element,

table"

; name = "Offset to the rotary table"

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5.2.3.5

$NK_TYPE

Function

The element type should be entered in the system variable:

Type

Description

AXIS_LIN

The element describes a linear machine axis (linear axis) with direction vector

(Page 415)

$NK_OFF_DIR and work offset $NK_A_OFF.

AXIS_ROT

The element describes a rotary machine axis (rotary axis) with direction vector

(Page 418)

$NK_OFF_DIR and work offset $NK_A_OFF or a spindle.

Note

The position of a spindle is considered differently depending on the function used by

the kinematic chain:

• Collision avoidance: Indeterminate position

• Kinematic transformation: Depending on the setting in $NT_CNTRL, bit 1-3, the

position corresponding to $NK_A_OFF or the speed setpoint is taken into consid-

eration

ROT_CONST

The element describes a constant rotation around direction vector $NK_OFF_DIR and

(Page 421)

angle $NK_A_OFF.

OFFSET

The element describes a constant linear offset with the offset vector $NK_OFF_DIR.

(Page 423)

SWITCH

The element defines a switch, which is switched using system variable $NK_SWITCH

(Page 425)

(Page 427).

Syntax

$NK_TYPE[<n>] = "<Typ>"

Meaning

$NK_TYPE:

Type of the element

Data type:

STRING

Default value:

"" (empty string)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<Typ>:

Element name, max. string length: 31 characters

Data type:

STRING

Range of values:

"AXIS_LIN", "AXIS_ROT", "ROT_CONST", "OFFSET", "SWITCH"

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5.2 Commissioning

Example

The 9th kinematic element is a rotary axis:

Program code

Comment

N100 $NK_TYPE[8] = "AXIS_ROT"

; 9th kin. element

; type = rotary axis

5.2.3.6

Type-dependent variables for $NK_TYPE = "AXIS_LIN"

$NK_OFF_DIR

Function

The direction vector along which the linear axis $NK_AXIS assigned to the element moves,

should be entered in the system variable. The output coordinate system therefore results from

the input coordinate system, offset by the current position value of the linear axis and the work

offset specified in $NK_A_OFF.

Supplementary conditions:

• The direction vector must be specified as an absolute value, i.e. in relation to the world

coordinate system.

• The direction vector must be specified so that it points in the positive traversing direction of

the machine axis.

• The absolute value of the direction vector must be greater than 1*10^-6.

Syntax

$NK_OFF_DIR[<n>,<k>] = <value>

Meaning

$NK_OFF_DIR:

Direction vector (X; Y; Z)

Data type:

REAL

Range of values:

Direction vector: 1*10^-6 < |Vector | ≤ max. REAL value

Default value:

(0.0, 0.0, 0.0)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<k>:

Coordinate index

Data type:

INT

Range of values:

0: X coordinate (abscissa)

1: Y coordinate (ordinate)

2: Z coordinate (applicate)

<value>:

Coordinate value

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ + max. REAL value

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5.2 Commissioning

Example

; The linear axis of the 9th element moves along the direction vector. The direction vector is the

unit vector (1; 0; 0), rotated around Z with γ=90° in the X/Y plane, and around X with α=10° in

the Y/Z plane referred to the world coordinate system. The following values result from this for

the individual components (x, y, z) of the direction vector:

• x = cos(γ) * cos(α) = cos(90) * cos(10) = 0.0

• y = sin(γ) * cos(α) = sin(90) * cos(10) ≈ 0.985

• z = sin(α) = sin(10) ≈ 0.174

=

˞

<

]

ˠ

[

;

\

Figure 5-6

Direction vector, general

Program code

Comment

; 9th kinematic element

N100 $NK_OFF_DIR[8,0] = COS(90)*COS(10)

; 0 = X component

N110 $NK_OFF_DIR[8,1] = SIN(90)*COS(10)

; 1 = Y component

N120 $NK_OFF_DIR[8,2] = SIN(10)

; 2 = Z component

$NK_AXIS

Function

The name of the machine axis (MD10000 $MN_AXCONF_MACHAX_NAME_TAB) that is to be

assigned to the element should be entered in the system variable.

The output coordinate system of the element results from the input coordinate system offset by

the current position setpoint of the machine axis in the MCS and the offset specified in

$NK_A_OFF. The position setpoint of the machine axis contains all the active work offsets and

corrections.

In accordance with the AXIS_LIN type entered in $NK_TYPE, the machine axis must be a linear

axis:

MD30300 $MA_IS_ROT_AX = 0

Syntax

$NK_AXIS[<n>] = <name>

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5.2 Commissioning

Meaning

$NK_AXIS:

Machine axis name

Data type:

STRING

Range of values:

Machine axis name

Default value:

"" (empty string)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<value>:

Machine axis name

Data type:

STRING

Range of values:

Machine axis names

Example

The 9th kinematic element is assigned the machine axis with the name V1 as linear axis.

Program code

Comment

N100 $NK_AXIS[8] = "V1"

; 9th kin. element

; axis = machine axis V1

$NK_A_OFF

Function

An additional work offset can be entered in the system variable for the assigned machine axis

($NK_AXIS). This work offset is only effective within the kinematic chain.

Syntax

$NK_A_OFF[<n>] = <value>

Meaning

$NK_A_OFF:

Work offset

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ ± max. REAL value

Default value:

0.0

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<value>:

Offset value

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ ± max. REAL value

Example

The linear axis zero point of the 9th kinematic element is moved by 30.0 mm compared to the

modelled kinematics.

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5.2 Commissioning

The unit in which the numerical value is interpreted depends on the current input system (inch/

metric).

Program code

Comment

N100 $NK_A_OFF[8] = 30.0

; 9th kin. element

; Work offset = 30.0 mm

5.2.3.7

Type-dependent variables for $NK_TYPE = "AXIS_ROT"

$NK_OFF_DIR

Function

The direction vector around which the rotary axis $NK_AXIS assigned to the element rotates,

should be entered in the system variable. The output coordinate system is therefore calculated

from the input coordinate system, rotated by the current position value of the rotary axis and the

offset specified in $NK_A_OFF around the direction vector $NK_OFF_DIR.

Supplementary conditions:

• The direction vector must be specified as an absolute value, i.e. in relation to the world

coordinate system.

• The direction vector must be specified so that, in accordance with the "right-hand rule", the

thumb points in the direction of the vector when the rotary axis turns in the positive

direction.

• The absolute value of the direction vector must be greater than 1*10^-6.

Note

Spindle

If the assigned machine axis is a spindle, its position is taken into account in different ways

specific to the function:

• Collision avoidance: Indeterminate position

• Kinematic transformation: depending on the setting in $NT_CNTRL, bit 1-3

- Bit x == 0 → indeterminate position

- Bit x == 1 → current position value + $NK_A_OFF,

Syntax

$NK_OFF_DIR[<n>,<k>] = <value>

Meaning

$NK_OFF_DIR:

Direction vector (X; Y; Z)

Data type:

REAL

Range of values:

Direction vector: 1*10^-6 < |Vector | ≤ max. REAL value

Default value:

(0.0, 0.0, 0.0)

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5.2 Commissioning

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<k>:

Coordinate index

Data type:

INT

Range of values:

0: X coordinate (abscissa)

1: Y coordinate (ordinate)

2: Z coordinate (applicate)

<value>:

Coordinate value

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ + max. REAL value

Example

The rotary axis of the 9th element rotates around the direction vector. The direction vector is the

unit vector (1; 0; 0), rotated around Z with γ=90° in the X/Y plane, and around X with α=10° in

the Y/Z plane referred to the world coordinate system. The following values result from this for

the individual components (x, y, z) of the direction vector:

• x = cos(γ) * cos(α) = cos(90) * cos(10) = 0.0

• y = sin(γ) * cos(α) = sin(90) * cos(10) ≈ 0.985

• z = sin(α) = sin(10) ≈ 0.174

=

˞

<

]

ˠ

[

;

\

Figure 5-7

Direction vector, general

Program code

Comment

; 9th kinematic element

N100 $NK_OFF_DIR[8,0] = COS(90)*COS(10)

; 0 = X component

N110 $NK_OFF_DIR[8,1] = SIN(90)*COS(10)

; 1 = Y component

N120 $NK_OFF_DIR[8,2] = SIN(10)

; 2 = Z component

$NK_AXIS

Function

The name of the machine axis (MD10000 $MN_AXCONF_MACHAX_NAME_TAB) that is to be

assigned to the element should be entered in the system variable.

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5.2 Commissioning

The output coordinate system of the element results from the input coordinate system rotated

through the current position setpoint of the machine axis in the MCS and the offset specified in

$NK_A_OFF. The position setpoint of the machine axis contains all the active work offsets and

corrections.

The machine axis type must correspond to the type entered in $NK_TYPE:

In accordance with the AXIS_ROT type entered in $NK_TYPE, the machine axis must be a rotary

axis:

MD30300 $MA_IS_ROT_AX = 1

Syntax

$NK_AXIS[<n>] = <name>

Meaning

$NK_AXIS:

Machine axis name

Data type:

STRING

Range of values:

Machine axis name

Default value:

"" (empty string)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<value>:

Machine axis name

Data type:

STRING

Range of values:

Machine axis names

Example

The 9th kinematic element is assigned the machine axis with the name B1 as rotary axis.

Program code

Comment

N100 $NK_AXIS[8] = "B1"

; 9th kin. element

; axis = machine axis B1

$NK_A_OFF

Function

An additional work offset can be entered in the system variable for the assigned machine axis

($NK_AXIS). This work offset is only effective within the kinematic chain.

Syntax

$NK_A_OFF[<n>] = <value>

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5.2 Commissioning

Meaning

$NK_A_OFF:

Work offset

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ ± max. REAL value

Default value:

0.0

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<value>:

Offset value

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ ± max. REAL value

Example

The rotary axis zero point of the 9th kinematic elements is moved through 30.0° compared to

the modelled kinematics.

Program code

Comment

N100 $NK_A_OFF[8] = 30.0

; 9th kin. element

; Work offset = 30.0°

5.2.3.8

Type-dependent variables for $NK_TYPE = "ROT_CONST"

$NK_OFF_DIR

Function

The direction vector around which the constant rotation is performed should be entered in the

system variable. The output coordinate system is therefore calculated from the input coordinate

system, rotated through the angle specified in $NK_A_OFF around the direction vector

$NK_OFF_DIR.

Supplementary conditions:

• The direction vector must be specified as an absolute value, i.e. in relation to the world

coordinate system.

• The direction vector must be specified so that, in accordance with the "right-hand rule", the

thumb points in the direction of the vector when the rotary axis turns in the positive

direction.

• The absolute value of the direction vector must be greater than 1*10^-6.

Syntax

$NK_OFF_DIR[<n>,<k>] = <value>

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Meaning

$NK_OFF_DIR:

Direction vector (X; Y; Z)

Data type:

REAL

Range of values:

Direction vector: 1*10^-6 < |Vector | ≤ max. REAL value

Default value:

(0.0, 0.0, 0.0)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<k>:

Coordinate index

Data type:

INT

Range of values:

0: X coordinate (abscissa)

1: Y coordinate (ordinate)

2: Z coordinate (applicate)

<value>:

Coordinate value

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ + max. REAL value

Example

The output coordinate system of the 9th Elements therefore arises from the input coordinate

system, rotated through the angle specified in $NK_A_OFF around the direction vector. The

direction vector is the unit vector (1; 0; 0), rotated around Z with γ=90° in the X/Y plane, and

around X with α=10° in the Y/Z plane referred to the world coordinate system. The following

values result from this for the individual components (x, y, z) of the direction vector:

• x = cos(γ) * cos(α) = cos(90) * cos(10) = 0.0

• y = sin(γ) * cos(α) = sin(90) * cos(10) ≈ 0.985

• z = sin(α) = sin(10) ≈ 0.174

=

˞

<

]

ˠ

[

;

\

Figure 5-8

ROT_CONST

Program code

Comment

; 9th kinematic element

N100 $NK_OFF_DIR[8,0] = COS(90)*COS(10)

; 0 = X component

N110 $NK_OFF_DIR[8,1] = SIN(90)*COS(10)

; 1 = Y component

N120 $NK_OFF_DIR[8,2] = SIN(10)

; 2 = Z component

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5.2 Commissioning

$NK_A_OFF

Function

The angle through which the output coordinate system is rotated compared with the input

coordinate system around the direction vector $NK_OFF_DIR should be entered in the system

variable.

Syntax

$NK_A_OFF[<n>] = <value>

Meaning

$NK_A_OFF:

Angle of rotation

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ + max. REAL value

Default value:

0.0

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<value>:

Angle

Data type:

REAL

Range of values:

- max. REAL value ≤ x ≤ + max. REAL value

Example

The angle of rotation of the 9th kinematic element is 30.0°.

Program code

Comment

N100 $NK_A_OFF[8] = 30.0

; 9th kin. element

; Angle of rotation = 30.0°

5.2.3.9

Type-dependent variables for $NK_TYPE = "OFFSET"

$NK_OFF_DIR

Function

The offset vector by which the output coordinate system is moved compared to the input

coordinate system should be entered in the system variable.

The offset vector must be specified as an absolute value, i.e. in relation to the world coordinate

system.

Syntax

$NK_OFF_DIR[<n>,<k>] = <value>

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5.2 Commissioning

Meaning

$NK_OFF_DIR:

Offset vector (X; Y; Z)

Data type:

REAL

Range of values:

(- max. REAL value) ≤ x ≤ (+ max. REAL value)

Default value:

(0.0, 0.0, 0.0)

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<k>:

Coordinate index

Data type:

INT

Range of values:

0: X coordinate (abscissa)

1: Y coordinate (ordinate)

2: Z coordinate (applicate)

<value>:

Coordinate value

Data type:

REAL

Range of values:

(- max. REAL value) ≤ x ≤ (+ max. REAL value)

Example

The output coordinate system of the 9th element is obtained from the input coordinate system,

offset through the offset vector (x, y, z) with the following coordinates referred to the world

coordinate system:

• x = 10.0

• y = 20.0

• z = 30.0

=

<

]

[

;

\

Figure 5-9

Offset vector

Program code

Comment

; 9th kinematic element

N100 $NK_OFF_DIR[8,0] = 10.0

; 0 = X component

N110 $NK_OFF_DIR[8,1] = 20.0

; 1 = Y component

N120 $NK_OFF_DIR[8,2] = 30.0

; 2 = Z component

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5.2 Commissioning

5.2.3.10

Type-dependent variables for $NK_TYPE = "SWITCH"

$NK_SWITCH_INDEX

Function

The switch is emulated using system variables $NK_SWITCH_INDEX and $NK_SWITCH_POS (see

the following paragraph)

Index i must be entered in $NK_SWITCH_INDEX, with which the switch is closed and opened via

system variable $NK_SWITCH[<i>].

Syntax

$NK_SWITCH_INDEX[<n>] = <i>

Meaning

$NK_SWITCH_

Index i, via which the switch is addressed using system variable $NK_SWITCH[<i>]

INDEX:

Data type:

INT

Range of values:

-1, 0, 1, 2, ... ($MN_MAXNUM_KIN_SWITCHES - 1)

-1: The state of the switch is always CLOSED

Default value:

-1

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<i>:

Index value

Data type:

INT

Example

The 9th element of the kinematic chain is a switch, which is activated by system variable

$NK_SWITCH[ 2 ].

Program code

Comment

; 9th element

N100 $NK_SWITCH_INDEX[8] = 2

; Index 2

$NK_SWITCH_POS

Function

A switch is emulated by system variables $NK_SWITCH_INDEX (see the previous paragraph) and

$NK_SWITCH_POS.

In $NK_SWITCH_POS, value p (close value) should be entered, where the switch is brought into

the CLOSED position by system variable $NK_SWITCH[<i>].

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Independent of $NK_SWITCH[<i>], the switch has the following states:

• CLOSED: The close value p of the switch, specified in $NK_SWITCH_POS is the same as the

actual value of $NK_SWITCH[<i>].

$NK_SWITCH_POS[<n>] == $NK_SWITCH[<i>]

The previous element of the kinematic chain is connected with the output, i.e. the following

element of the switch specified in $NK_NEXT.

• OPEN: The close value of the switch, specified in $NK_SWITCH_POS, is not the same as the

actual value of $NK_SWITCH[<i>].

$NK_SWITCH_POS[<n>] ≠ $NK_SWITCH[<i>]

The previous element of the kinematic chain is notconnected with the output, i.e. the

following element of the switch specified in $NK_NEXT.

The close value can be freely selected.

Note

Parallel element $NK_PARALLEL

The connection to a parallel element specified in $NK_PARALLEL is not influenced by the switch.

This means that the previous element is always connected to the element in the branch parallel

with the switch.

Syntax

$NK_SWITCH_POS[<n>] = <p>

Meaning

$NK_SWITCH_

Close value

POS:

Data type:

INT

Range of values:

0 ≤ x ≤ positive max. INT value

Default value:

0

<n>:

System variable or element index

Data type:

INT

Range of values:

0, 1, 2, ... ($MN_MM_MAXNUM_KIN_CHAIN_ELEM - 1)

<p>:

Value for switch position CLOSED

Data type:

INT

Example

The 9th element of the kinetic chain is a switch, which is closed if $NK_SWITCH[ 3 ] == 1

Program code

Comment

; 9th element

N110 $NK_SWITCH_POS[8] = 1

; switch position = 1

See also

$NK_SWITCH (Page 427)

$MN_MAXNUM_KIN_SWITCHES (Page 409)

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$MN_MM_MAXNUM_KIN_CHAIN_ELEM (Page 409)

5.2.3.11

$NK_SWITCH

Function

The switch variable comprises an array of switch positions i. The actual switch positions p should

be entered in this array.

Function

To parameterize (Page 425) a switch_i in a kinematic chain, switch_iwith index i must be connected

to the switch variable and its switch position p for the CLOSED state assigned to it.

$NK_SWITCH_INDEX[<n>] = <i>

$NK_SWITCH_POS[<n>]

= <p>

Switch_i can then be closed and opened via index i of the switch variable:

Close: $NK_SWITCH[<i>] = <p>

Open: $NK_SWITCH[<i>] ≠ <p>

As many switches as required can be connected with an index of the switch variable.

Syntax

$NK_SWITCH[<i>] = <p>

Meaning

$NK_SWITCH<i>:

Switch variable with switch positions i

Data type:

INT

Value range:

-1 ≤x ≤ positive max. INT value

Note

-1: Initial state OPEN

<i>:

Switch index

Data type:

INT

Range of values:

0, 1, 2, ... (MD18882 $MN_MM_MAX_NUM_KIN_SWITCHES - 1)

<p>:

Switch setting

Data type:

INT

Value range:

-1 ≤x ≤ positive max. INT value

-1: Initial state OPEN

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5.3 Programming

Meaning

DELOBJ:

Deletion of elements from kinematic chains, protection areas, protection area ele-

ments, collision pairs and transformation data

<CompType>:

Component type to be deleted

Data type:

STRING

Value: "KIN_CHAIN_ELEM"

Meaning: System variables of all kinematic elements: $NK_...

Value: "KIN_CHAIN_SWITCH"

Meaning: System variable $NK_SWITCH[<i>]

Value: "KIN_CHAIN_ALL"

Meaning: All kinematic elements and switches.

Is the same as the successive call of DELOBJ with "KIN_CHAIN_ELEM" and

"KIN_CHAIN_SWITCH"

Value: "PROT_AREA"

Meaning: System variables of the protection areas:

• $NP_PROT_NAME

• $NP_CHAIN_NAME

• $NP_CHAIN_ELEM

• $NP_1ST_PROT

Value: "PROT_AREA_ELEM"

Meaning: System variables of the protection area elements of machine protection

areas and/or automatic tool protection areas:

• $NP_NAME

• $NP_NEXT

• $NP_NEXTP

• $NP_COLOR

• $NP_D_LEVEL

• $NP_USAGE

• $NP_TYPE

• $NP_FILENAME

• $NP_PARA

• $NP_OFF

• $NP_DIR

• $NP_ANG

Value: "PROT_AREA_COLL_PAIRS"

Meaning: System variables of the collision pairs:

• $NP_COLL_PAIR

• $NP_SAFETY_DIST

Value: "PROT_AREA_ALL"

Meaning: All protection areas, protection area elements and collision pairs (system

variable $NP_... )

Is the same as the successive call of DELOBJ with "PROT_AREA," "PROT_AREA_ELEM,"

and "PROT_AREA_COLL_PAIRS"

Value: "TRAFO_DATA"

Meaning: System variables of all transformations $NT_...

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5.3 Programming

<Index1>:

Index of the first component to be deleted (optional)

Data type:

INT

Default value:

-1

Value range:

-1 ≤ x ≤ (maximum number of configured components -1)

Value

Meaning

0, 1, 2,

Index of the component to be deleted

-1

All components of the specified type are deleted. <Index2> is not

evaluated.

<Index2>:

Index of the last components to be deleted (optional)

If <Index2> is not programmed, only the system variables of the component refer-

enced in <Index1> are deleted.

Data type:

INT

Default value:

Only the system variables of the component referenced in <In-

dex1> are deleted.

Value range:

<Index1> < x ≤ (max. number of configured components -1)

<NoAlarm>:

Alarm suppression (optional)

Data type:

BOOL

Default value:

FALSE

Value

Meaning

FALSE

In the event of an error (<RetVal> < 0), program processing is stop-

ped and an alarm displayed.

TRUE

In the event of an error, the program processing is not stopped and

no alarm displayed.

Application: User-specific reaction corresponding to the return val-

ue

<RetVal>:

Function return value

Data type:

INT

Value range:

0, -1, -2, ... -7

Value

Meaning

0

No error occurred

-1

Call of the function without parameters. At least parameter

<CompType> must be specified.

-2

<CompType> identifies an unknown component

-3

<Index1> is less than -1

-4

<Index1> is greater than the configured number of components

-5

<Index1> has a value not equal to -1 when deleting a compo-

nent group

-6

<Index2> is less than <Index1>

-7

<Index2> is greater than the configured number of components

-8

Insufficient write permission

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Kinematic chain

5.3 Programming

5.3.2

Index determination by means of names (NAMETOINT)

User-specific names are entered in the system variable arrays of type STRING. Based on the

identifier of the system variables and the name, the NAMETOINT() function determines the

index value belonging to the name under which it is stored in the system variable array.

Syntax

<RetVal> = NAMETOINT(<SysVar>,<Name>[,<NoAlarm>])

Meaning

NAMETOINT:

Determining the system variable index

<SysVar>:

Name of the system variable array of typeSTRING

Data type:

STRING

Range of val-

Name of all NC system variable arrays of type STRING

ues:

<Name>:

Character string or name for which the system variable index is to be determined.

Data type:

STRING

<NoAlarm>:

Alarm suppression (optional)

Data type:

BOOL

Default value:

FALSE

Value

Meaning

TRUE

In the event of an error, the program processing is not stopped and

no alarm displayed.

Application: User-specific reaction corresponding to the return val-

ue

FALSE

In the event of an error (<RetVal> < 0), program processing is stop-

ped and an alarm displayed.

<RetVal>:

System variable index or error message

Data type:

INT

Range of val-

-1 ≤ x ≤ (max. number of configured components -1)

ues:

Value

Meaning

≥ 0

The sought name has been found under the specified system var-

iable index.

-1

The sought name has not been found or an error has occurred.

Example

Program code

Comment

DEF INT INDEX

$NP_PROT_NAME[27]="Cover"

INDEX = NAMETOINT("$NP_PROT_NAME","Cover")

; INDEX == 27

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Kinematic chain

5.4 Example

5.4

Example

5.4.1

Specifications

General Information

The principle approach when parameterizing a kinematic chain with three switches using a part

program is shown using as example a 5-axis machine with three different tool heads, which are

used alternately. All of the system variables, relevant for kinematic chain, are written to the part

program:

• Kinematic chain $NK_...

Option and machine data

The following option and machine data must be set for the example:

• MD19830 $ON_COLLISION_MASK.Bit 0 = 1

• MD18880 $MN_MM_MAXNUM_KIN_CHAIN_ELEM = 15

Kinematic chain

Schematic representation of the machine kinematics

& $ $;,6

2))6(7

& $

;,6

6

+($'

6

+($'

; $;,6

6

+($'

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Kinematic chain

5.4 Example

Elements of the kinematic chain

5RRW

; $;,6

<$;,6

= $;,6

& $;,6

& $;,6

2))6(7

$;,6B/,1

$;,6B/,1

$;,6B/,1

2))

$;,6B527

2))6(7

'2&.B3B

+($'

6:,7&+

2))6(7

'2&.B3B

+($'

6:,7&+

2))6(7

& $ $;,6

$ $;,6

722/ 5()

'2&.B3B

+($'

2))

$;,6B527

2))6(7

6:,7&+

2))6(7

2))6(7

The kinematic chain starts with an element of the type "Offset". When completely

parameterizing the collision avoidance, these are assigned to all static protection areas of the

machine

The offset element is followed by the kinematic elements of the linear machine axes X, Y and Z

- as well as the offset and kinematic elements of rotary axes C and A.

The offset element for the reference point of the tool heads is followed by three switches to

switch on and switch off the tool heads. As a result of $NK_INDEX = 3 all three switches refer to

the same switch variable $NK_SWITCH[ 3 ]. As a result of the different switch positions (1, 2, 3),

only the subchain of the active tool head is active.

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433

Kinematic chain

5.5 Data lists

Program code

; ----------------------------------------------------------

; Kinematic element: OFFSET: HEAD 3

; ----------------------------------------------------------

N870 $NK_TYPE[KIE_CNTR] = "OFFSET"

N880 $NK_NAME[KIE_CNTR] = "HEAD 3"

N890 $NK_NEXT[KIE_CNTR] = ""

;

N900 $NK_OFF_DIR[KIE_CNTR,0] = 50

; X direction

N910 $NK_OFF_DIR[KIE_CNTR,1] = -20

; Y direction

N920 $NK_OFF_DIR[KIE_CNTR,2] = -90

; Z direction

N930 KIE_CNTR = KIE_CNTR + 1

End

5.5

Data lists

5.5.1

Machine data

5.5.1.1

NC-specific machine data

Number

Identifier: $MN_

Description

16800

ROOT_KIN_ELEM_NAME

Name of the first element in the kinematic chain

18880

MM_MAXNUM_KIN_CHAIN_ELEM

Maximum number of elements for kinematic chains

18882

MM_MAX_NUM_KIN_SWITCHES

Maximum number of switches for kinematic chains

5.5.2

System variables

Identifier

Description

$NK_NAME

Name of the kinematic element

$NK_NEXT

Name of the next element in the kinematic chain

$NK_PARALLEL

Name of the first element of a parallel branching kinematic chain before the

element

$NK_TYPE

Type of the kinematic element

$NK_OFF_DIR

Depends on $NK_TYPE: Offset or direction vector

$NK_AXIS

Name of the assigned machine axis or object name

$NK_A_OFF

Work offset in the element for linear or rotary axes

$NK_SWITCH_INDEX

Index i, via which the switch is addressed using system variable

$NK_SWITCH[<i>]

$NK_SWITCH_POS

Switch position CLOSED

$NK_SWITCH

Switch variable

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Continuous-path mode, exact stop, LookAhead

6.2 Exact stop mode

Exact stop condition

The following exact stop conditions can be set:

• "Exact stop coarse"

• "Exact stop fine"

• "Interpolator end"

Application

Exact stop mode should always be used when the programmed contour must be executed

exactly.

Activation

In a program, exact stop operation can be specified using the following commands, either modal

or for specific blocks:

Command

Meaning

G60

Exact stop operation is effective from the current modal block.

G9

Exact stop operation is effective in the current block.

Exact stop conditions - "Exact stop coarse" and "Exact stop fine"

The exact stop condition "coarse" or "fine" is fulfilled by a machine axis if its current following

error is less than or equal to the tolerance range around the setpoint position, parameterized in

the machine data:

• MD36000 $MA_STOP_LIMIT_COARSE (exact stop coarse)

• MD36010 $MA_STOP_LIMIT_FINE (exact stop fine)

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H[DFW VWRS FRDUVH

'%

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Setpoint position

W

Figure 6-1

Tolerance window of exact stop conditions

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Continuous-path mode, exact stop, LookAhead

6.2 Exact stop mode

Note

The tolerance windows of the exact stop conditions "Exact stop coarse" and "Exact stop fine"

should be assigned in such a way that the following requirement is fulfilled:

"Exact stop coarse" > "Exact stop fine"

Exact stop condition, "Interpolator end"

With exact stop condition "Interpolator end", the block change to the next block takes place as

soon as all path axes and non-modal special axes involved in the traversing motion have reached

the position programmed in the block in terms of the setpoint value. That is, the interpolator has

executed the block.

The actual position and the following error of the relevant machine axes are not taken into

consideration for exact stop condition "Interpolator end". Thus, depending on the dynamic

response of the machine axes, this can result in a relatively large smoothing of the contour at the

block changes in comparison to the exact stop conditions "Exact stop coarse" and "Exact stop

fine".

Activating the programmable exact stop conditions

The programmable exact stop conditions are activated using the following commands:

Command

Exact stop condition

G601

Exact stop fine

G602

Exact stop coarse

G603

Interpolator end

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443

Continuous-path mode, exact stop, LookAhead

6.2 Exact stop mode

Block change depending on exact stop condition

The figure below illustrates the block change timing in terms of the selected exact stop condition.

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9HORFLW\ VHWSRLQW

Setpoint position

W

① Set position/block change points G603

② G602 MD36000 $MA_STOP_LIMIT_COARSE

③ G601 MD36010 $MA_STOP_LIMIT_FINE

Figure 6-2

Block change depending on exact stop condition

Weighting factor for exact stop conditions

A parameter set-dependent evaluation of the exact stop conditions can be specified via the

following axis-specific machine data:

MD36012 $MA_STOP_LIMIT_FACTOR[<Parameter set>] = <Value>

The evaluation factor is applied to the values of the following machine data:

• MD36000 $MA_STOP_LIMIT_COARSE

• MD36010 $MA_STOP_LIMIT_FINE

• MD36030 $MA_STANDSTILL_POS_TOL

Application examples

• Adaptation of the positioning response to different mass ratios, such as after a new gearbox

stage has been selected.

• Reduction in positioning time, depending on various machining states, such as roughing and

finishing

Parameterizable input of the effective exact stop conditions

The exact stop conditions for the commands of the 1st G group can be defined permanently. As

a consequence, programmed exact stop conditions are no longer effective.

Exact stop conditions can be set independently of one another for the following commands:

• Rapid traverse G0

• All other commands of the 1st G group

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Continuous-path mode, exact stop, LookAhead

6.2 Exact stop mode

The exact stop condition is set on a channel-for-channel basis using the following decimal-coded

machine data:

MD20550 $MC_EXACT_POS_MODE = <Z><E>

Z

E

Effective exact stop condition

0

0

Programmed exact stop condition

1

1

G601 (Exact stop window fine)

2

2

G602 (Exact stop window coarse)

3

3

G603 (Interpolator end)

E (ones position): Setting the exact stop condition für rapid traverse.

Z (tens position): Setting the exact stop condition for all other commands of the 1st G group

Example

MD20550 $MC_EXACT_POS_MODE = 02

• <E> = 2: With rapid traverse, exact stop condition G602 (exact stop window coarse) is always

active, irrespective of any programming.

• <Z> = 0: When traversing with all other commands of the 1st G group, the programmed exact

stop condition applies.

Block change behavior for block transitions from G0 ↔ non-G0 to continuous path mode

For the continuous path mode, the block change behavior between rapid traverse and non rapid

traverse blocks (G0 ↔ non-G0) can be set using the following machine data:

MD20552 $MC_EXACT_POS_MODE_G0_TO_G1 = <Value>

<Val-

Meaning

ue>

0

No additional stop at the block transition.

1

Stop at the block transition.

The behavior corresponds to G601 (exact stop window, fine)

2

Stop at the block transition.

The behavior corresponds to G602 (exact stop window, coarse)

3

Stop at the block transition.

The behavior corresponds to G603 (interpolator end)

4

No stop at the block transition.

For the continuous path mode, for block changes from G0 → non-G0, in the G0 block, the

actual value of the feedrate correction of the subsequent non-G0 block is predicatively taken

into account. Depending on the axis dynamic performance and the path length of the current

block, the block change is executed with the exact or the best possible adapted velocity of the

following block.

5

No stop at the block transition.

For the continuous path mode, for block changes from G0 → non-G0 and non-G0 → G0, the

current value of the feedrate correction (G0 → non-G0) or the rapid traverse contour (non-

G0 → G0) of the following block is predicatively taken into account. Depending on the axis

dynamic performance and the path length of the current block, the block change is executed

with the exact or the best possible adapted velocity of the following block.

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445

Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

\

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[

3DWK YHORFLW\

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W

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$[LDO

*UDGLHQW D[

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Figure 6-3

Axial velocity change on block transition

With a practically tangential block transition, the path velocity is not reduced if the permissible

axial accelerations are not exceeded. This means that very small bends in the contour (e.g. 0.5°)

are overtraveled directly.

Overload factor

The overload factor restricts step changes in the machine axis velocity at block ends. To ensure

that the velocity jump does not exceed the maximum load on the axis, the jump is derived from

the acceleration of the axis.

The overload factor indicates the extent by which the acceleration of the machine axis

(MD32300 $MA_MAX_AX_ACCEL) may be exceeded for an IPO-cycle.

The velocity jump results as follows:

Velocity jump = axis acceleration * (overload factor-1) * interpolator cycle.

The overload factor is saved in the machine data:

MD32310 $MA_MAX_ACCEL_OVL_FACTOR (overload factor for axial velocity jumps)

Factor 1.0 means that only tangential transitions with finite velocity can be traversed. For all

other transitions, the velocity is reduced to zero by changing the setpoint. This behavior is

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

6.3.3.1

Rounding according to a path criterion (G641)

Function

In continuous-path mode with rounding according to a path criterion, the size of the rounding

area is influenced by the path criteria ADIS and ADISPOS.

The path criteria ADIS and ADISPOS describe the maximum distances which a rounding block can

occupy before and after a block.

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$',6

3URJUDPPHG

$',6326

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EORFN

Note

Acute angles produce rounding curves with a large degree of curvature and therefore cause a

corresponding reduction in velocity.

Note

ADISPOS is programmed in the same way as ADIS, but must be used specifically for movements

in rapid traverse mode G0.

Scope of the path criterion

• ADIS or ADISPOS must be programmed. If the default is "zero", G641 behaves like G64.

• If only one of the blocks involved is rapid traverse G0, the smaller rounding distance applies.

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

•

If a very small value is used for ADIS, the controller must make sure that every interpolated

block, even an intermediate rounding block, contains at least one interpolation point. The

maximum path velocity is thereby limited to ADIS / interpolator cycle.

•

Irrespective of ADIS and ADISPOS, the rounding area is limited by the block length.

In blocks with short distances (distance < 4* ADIS and < 4 * ADISPOS respectively), the

rounding distance is reduced so that a traversable part of the original block is retained. The

remaining length depends on the axis path and is approximately 60% of the distance still to

be traversed in the block. ADIS or ADISPOS is therefore reduced to the remaining 40% of the

distance to be traversed. This algorithm prevents a rounding block being inserted for a very

small change in contour. In this case, switchover to continuous-path mode G64 is automatic

until rounding blocks can be inserted again.

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1

1

1

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1

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Figure 6-4

Path with limitation of ADIS

Activation/deactivation

Continuous-path mode with rounding based on a path criterion can be activated in any NC part

program block by the modal command G641. Before or on selection, the path criteria ADIS/

ADISPOS must be specified.

Selecting the exact stop which works on a block-by-block basis enables rounding to be

interrupted (G9).

Continuous-path mode with rounding based on a path criterion (G641) can be deactivated by

selecting:

• Modal exact stop (G60)

• Continuous-path mode G64, G642, G643, G644 or G645

Program example

Program code

Comment

N1 G641 Y50 F10 ADIS=0.5

; Continuous-path mode with rounding based on a path

criterion (rounding clearance: 0.5 mm)

N2 X50

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Program code

Comment

N3 X50.7

N4 Y50.7

N5 Y51.4

N6 Y51.0

N7 X52.1

6.3.3.2

Rounding in compliance with defined tolerances (G642/G643)

Function

In continuous-path mode involving rounding in compliance with defined tolerances, the

rounding normally takes place while adhering to the maximum permissible path deviation.

Instead of these axis-specific tolerances, the maintenance of the maximum contour deviation

(contour tolerance) or the maximum angular deviation of the tool orientation (orientation

tolerance) can be configured.

Activation

Continuous-path mode with rounding in compliance with defined tolerances can be activated in

any NC part program block by the modal command G642 or G643.

Selecting the exact stop which works on a block-by-block basis enables rounding to be

interrupted (G9).

Continuous-path mode with rounding in compliance with defined tolerances (G642/G643) can

be deactivated by selecting:

• Modal exact stop (G60)

• Continuous-path mode G64, G641, G644 or G645

Differences between G642 - G643

With regard to their rounding behavior, commands G642 and G643 differ as follows:

G642

G643

With G642, the rounding path is determined on the

In the case of G643, each axis may have a different

basis of the shortest distance for rounding all axes.

rounding path. The rounding travels are taken into

This value is taken into account when generating a

account axis-specifically and block-internally (⇒ no

rounding block.

separate rounding block).

With G642, the rounding area results from the

Very different specifications for the contour toler-

smallest tolerance setting.

ance and the tolerance of the tool orientation can

only have effect with G643.

Parameterization

Maximum path deviation

The maximum path deviation permitted with G642/G643 is set for each axis in the machine data:

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

MD33100 $MA_COMPRESS_POS_TOL

Contour tolerance and orientation tolerance

The contour tolerance and orientation tolerance are set in the channel-specific setting data:

SD42465 $SC_SMOOTH_CONTUR_TOL (maximum contour deviation)

SD42466 $SC_SMOOTH_ORI_TOL (maximum angular deviation of the tool orientation)

The settings data can be programmed in the NC program and can in this way be specified

differently for each block transition.

Note

The setting data SD42466 $SC_SMOOTH_ORI_TOL is effective only in active orientation

transformation.

Rounding behavior

Rounding behavior with G642 and G643 is configured via the machine data:

MD20480 $MC_SMOOTHING_MODE (rounding behavior with G64x)

The units positions (E) define the behavior for G643, the tens positions (Z) the behavior for G642:

Value E or Z

Meaning

0

All axes:

Rounding by maintaining the maximum permitted path deviation:

MD33100 $MA_COMPRESS_POS_TOL

1

Geometry axes:

Rounding by maintaining the contour tolerance:

SD42465 $SC_SMOOTH_CONTUR_TOL

Remaining axes:

Rounding by maintaining the maximum permitted path deviation:

MD33100 $MA_COMPRESS_POS_TOL

2

Geometry axes:

Rounding by maintaining the orientation tolerance:

SD42466 $SC_SMOOTH_ORI_TOL

Remaining axes:

Rounding by maintaining the maximum permitted path deviation:

MD33100 $MA_COMPRESS_POS_TOL

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Value E or Z

Meaning

3

Geometry axes:

Rounding by maintaining the contour tolerance and the orientation tolerance:

SD42465 $SC_SMOOTH_CONTUR_TOL

SD42466 $SC_SMOOTH_ORI_TOL

Remaining axes:

Rounding by maintaining the maximum permitted path deviation:

MD33100 $MA_COMPRESS_POS_TOL

4

All axes:

The rounding length programmed with ADIS or with ADISPOS is used (as in case of

G641).

Any axis-specific tolerance or contour and orientation tolerance specifications are ig-

nored.

Profile for limit velocity

The use of a velocity profile for rounding in compliance with defined tolerances is controlled via

the hundreds position in MD20480:

Value

Meaning

< 100:

A profile of the limit velocity is calculated within the rounding area, based on the defined

maximum values for acceleration and jerk on the participating axes or path.

This can lead to an increase in the path velocity in the rounding area and therefore to the

acceleration of the participating axes.

≥100:

A profile of the limit velocity is not calculated for rounding blocks with G641/G642. A

constant velocity limit is specified instead.

This prevents the participating axes being accelerated into the rounding area during

rounding with G641/G642. However, in certain cases, this setting can cause the rounding

blocks to be traversed too slowly, especially in large rounding areas.

1xx:

No velocity profile for G641

2xx:

No velocity profile for G642

Note

MD28530 $MC_MM_PATH_VELO_SEGMENTS (number of memory elements for limiting the

path velocity)

Supplementary conditions

Restriction for protection zones with active radius compensation and tool orientation:

Although tool radius compensation is applied for a tool orientation, which is not perpendicular

to one of the three datum planes of the basic coordinate system, the protection zones are not

rotated onto the corresponding plane.

For G643 the following must apply:

MD28530 $MC_MM_PATH_VELO_SEGMENTS > 0 (number of memory elements for limiting the

path velocity)

If this condition is met, then it must be applicable for all axes:

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6.3 Continuous-path mode

MD35240 $MC_ACCEL_TYPE_DRIVE = FALSE (acceleration characteristic DRIVE for axes on/off)

6.3.3.3

Rounding with maximum possible axial dynamic response (G644)

Function

Maximizing the dynamic response of the axes is key to this type of continuous-path mode with

smoothing.

Note

Smoothing with G644 is only possible under the following conditions:

• All of the participating axes contain only one linear motion in the two blocks under

consideration.

• A kinematic transformation is not active.

If a participating axis contains a polynomial (polynomial programmed, spline active, compressor

active) or a kinematics transformation is active (PTP travel temporarily deactivates a kinematics

transformation), the block transition is smoothed with G642.

Activation

Continuous-path mode with smoothing with the maximum possible axial dynamic response can

be activated in any NC part program block by the modal command G644.

Selecting the exact stop which works on a block-by-block basis enables smoothing to be

interrupted (G9).

Continuous-path mode with smoothing with the maximum possible axial dynamic response

(G644) can be deactivated by selecting:

• Modal exact stop (G60)

• Continuous-path mode G64, G641, G642, G643 or G645

Parameter assignment

Smoothing behavior with G644 is configured via the thousands and tens of thousands places in

the machine data:

MD20480 $MC_SMOOTHING_MODE (smoothing behavior with G64x)

Value

Meaning

Thousand's place:

0xxx:

When smoothing with G644, the maximum deviations for each axis specified by the following

machine data are respected:

MD33100 $MA_COMPRESS_POS_TOL

If the dynamics of the axis permit, then any specified tolerance is not utilized.

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Value

Meaning

1xxx:

Specification of the maximum smoothing path by programming ADIS=...

or ADISPOS=... (as for G641).

2xxx:

Input the maximum possible frequencies of each axis in the smoothing area using the ma-

chine data:

MD32440 $MA_LOOKAH_FREQUENCY (smoothing frequency for LookAhead)

The smoothing area is defined so that no frequencies in excess of the specified maximum can

occur while the smoothing motion is in progress.

3xxx:

Any axis that has a velocity jump at a corner traverses around the corner with the maximum

possible dynamic response (maximum acceleration and maximum jerk).

SOFT:

If SOFT is active, the maximum acceleration and the maximum jerk of each axis are main-

tained.

BRISK:

If BRISK is active, only the maximum acceleration and not the maximum jerk of each axis is

maintained.

With this setting, neither the maximum deviations nor the smoothing distance are checked.

The resulting deviations or smoothing distances are determined exclusively by the dynamic

limits of the respective axis and the current path velocity.

4xxx:

As in case of 0xxx, the maximum deviations of each axis specified with the following machine

data are used:

MD33100 $MA_COMPRESS_POS_TOL

Contrary to 0xxx, the specified tolerance is also utilized, if possible. Therefore, the axis does

not attain its maximum possible dynamics.

5xxx:

As in case of 1xxx, the maximum possible smoothing path is specified through programming

of ADIS=... or ADISPOS=... respectively.

Contrary to 1xxx, the specified smoothing path is also utilized, if possible. Therefore, the axes

involved do not attain their maximum possible dynamics.

Ten thousands digit

0xxxx

The velocity profiles of the axes in the smoothing area are determined without jerk limiting

for BRISK and with jerk limiting for SOFT.

1xxxx

The velocity profiles of the axes in the smoothing area are always determined with jerk

limiting, regardless of whether BRISK or SOFT is active.

When specifying the maximum axial deviations (MD33100 $MA_COMPRESS_POS_TOL) or the

maximum smoothing distance (ADIS / ADISPOS) the available smoothing path is normally not

used, if permitted by the dynamic response of the axes involved. Through this, the length of the

smoothing path depends on the active path feedrate. In case of lower path speeds, one gets

lower deviations from the programmed contours. However, it can be set that in these cases the

specified maximum axial deviation or the specified smoothing distance is utilized, if possible. In

this case the deviations depend on the programmed contour independent of the programmed

path feedrate.

Note

Apart from the ones mentioned, the following limitation can also become active additionally:

The smoothing distance cannot exceed half the length of the original participating blocks.

Basic functions

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Jerk limitation

The smoothing of the velocity jump on each axis and thus the shape of the smoothing path

depends on whether an interpolation is performed with or without jerk limitation.

Without jerk limitation the acceleration of each axis reaches its maximum value in the entire

smoothing area:

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7LPH

With jerk limitation, the jerk of each axis is limited to its maximum value within the smoothing

area. The smoothing motion thus generally consists of 3 phases(① ... ③):

9HORFLW\

7LPH

① During phase 1, each axis builds up its maximum acceleration. The jerk is constant and equal to the

maximum possible jerk on the respective axis.

② During phase 2, the maximum permissible acceleration is applied.

③ During phase 3, which is the last phase, the acceleration of each axis is reduced back to zero with

the maximum permissible jerk.

6.3.3.4

Rounding of tangential block transitions (G645)

Function

In continuous-path mode with rounding, rounding blocks are also only generated on tangential

block transitions if the curvature of the original contour exhibits a jump in at least one axis.

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

6.3.3.5

Rounding and repositioning (REPOS)

If the machining in the area of the rounding contour is interrupted, a REPOS operation cannot

be used to position again directly on the rounding contour. In this case, positioning can be made

only on the programmed contour.

Example

Programmed: Two traversing blocks N10 and N20 with programmed rounding G641.

The traversing motion is interrupted in the rounding area. The axes, e.g. manually, are then

traversed to the REPOS start point. Depending on the selected REPOS mode, the repositioning

on the contour is made at the points ①, ② or ③.

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Repositioning at the start of the interrupted traversal block

RMIBL

Repositioning at the interruption location

RMEBL

Repositioning at the end of the interrupted traversal block

RMNBL

Repositioning at the next contour point

①

Block start N10

②

To the REPOS start point of the next contour point

③

Block end N10 / block start N20

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

6.3.4

LookAhead

6.3.4.1

Standard functionality

Function

LookAhead is a function which is active in continuous-path mode (G64, G64x) and determines

a foreseeable velocity control for multiple NC part program blocks over and beyond the current

block.

Note

LookAhead is only available for path axes, not for spindles and positioning axes.

If a part program contains consecutive blocks with very small paths, only one velocity is reached

per block without LookAhead, enabling deceleration of the axes at the end of the block while

maintaining acceleration limits. This means that the programmed velocity is not reached at all.

With LookAhead, however, it is possible to implement the acceleration and deceleration phase

over multiple blocks with approximately tangential block transitions, thereby achieving a higher

feedrate with shorter distances.

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Velocity control with short distances and exact stop G60 or continuous-path mode G64 with

LookAhead

Deceleration to velocity limits is possible with LookAhead such that violation of the acceleration

and velocity limit is prevented.

LookAhead takes plannable velocity limits into consideration such as:

• Exact stop at block end

• Velocity limit in the block

• Acceleration limit in the block

• Velocity limit on block transition

• Synchronization with block change at block transition.

Basic functions

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Mode of operation

LookAhead carries out a block-specific analysis of velocity limits and specifies the required brake

ramp profile based on this information. LookAhead is adapted automatically to block length,

braking capacity and permissible path velocity.

For safety reasons, the velocity at the end of the last prepared block must initially be assumed

to be zero because the next block might be very small or be an exact-stop block, and the axes

must have been stopped by the end of the block.

With a series of blocks with high set velocity and very short paths, the speed can be increased

in each block depending on the velocity value currently calculated by the LookAhead function

in order to achieve the required set velocity. After this it can be reduced so that the velocity at

the end of the last block considered by the LookAhead function can be zero. This results in a

serrated velocity profile (see the following fig.) which can be avoided by reducing the set velocity

or increasing the number of blocks considered by the LookAhead function.

Y

9_VHWSRLQW

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1

1

1

1

1

1

W

Figure 6-6

Example for modal velocity control (number of blocks considered by the LookAhead function

= 2)

Activation/deactivation

LookAhead is activated by selecting continuous-path mode G64, G641, G642, G643, G644 or

G645.

Selecting the exact stop which works on a non-modal basis enables rounding to be interrupted

(G09).

LookAhead is deactivated by selecting the modal exact stop (G60).

Parameterization

Number of blocks

To achieve reliable axis traversal in continuous-path mode, the feedrate must be adapted over

several blocks. The number of blocks considered by the LookAhead function is calculated

automatically and can, if required, be limited by a machine data. The default setting is "1", which

means that LookAhead only considers the following block for velocity control.

Because LookAhead is especially important for short blocks (relative to the deceleration path),

the number of blocks required is of interest for LookAhead braking. It is sufficient to consider the

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Value

Meaning

TRUE

Function active

FALSE

Function not active

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

- MD20400 $MC_LOOKAH_USE_VELO_NEXT_BLOCK = 1

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A combination of both procedures (determination of following block velocity and determination

of override points) can be used to calculate the velocity profiles and is generally advisable

because the preset machine data for these functions already takes the widest range of override-

dependent velocity limits into account.

Note

If neither of the procedures has been activated, the setpoint velocity is always applied in the

current block.

Note

Plannable velocity limits restrict override-specific velocity limits.

Relief factor with block cycle problems

Block cycle problems are encountered in cases where the traversing distances of the NC blocks

to be processed are so short that the LookAhead function has to reduce the machine velocity to

provide enough time for block processing. In this situation, constant braking and acceleration

of path motion may occur.

Velocity fluctuations of this type can be dampened by specifying a relief factor:

MD20450 $MC_LOOKAH_RELIEVE_BLOCK_CYCLE (relieving factor for the block cycle time)

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Activation

This function is only effective with the following conditions:

• AUTOMATIC mode active

• "Acceleration with jerk limitation (SOFT)" mode active

Parameterization

Working memory

The memory for the "Free-form surface mode: Extended function" is configured via the machine

data:

MD28533 $MC_MM_LOOKAH_FFORM_UNITS = <value>

The required memory depends on the part program, the block lengths, the axis dynamic

response, as well as on an active kinematic transformation.

The following setting applies as a guideline for machining free-form surfaces: MD28533 = 18

Note

Due to the additional storage requirements, MD28533 should only be set for the channels in

which free-form surfaces are being machined.

Number of NC blocks in the IPO buffer

It is generally advisable to significantly increase the configured number of NC blocks in the

interpolation buffer when using the "Free-form surface mode: Extension function":

MD28060 $MC_MM_IPO_BUFFER_SIZE > 100

If the block memory capacity is too low, this may diminish the uniformity of the path-velocity

profile.

Activation/deactivation

The function can be switched on or off independently for every dynamic response mode (see

Section "Dynamic response mode for path interpolation (Page 484)"):

MD20443 $MC_LOOKAH_FFORM[<n>]= <value>

Index <n>

Dynamic response mode

<Value>

Free-form surface mode: Extension

function

0

Standard dynamic response set-

0

Off

tings (DYNNORM)

1

On

1

Positioning mode, tapping (DYN-

0

Off

POS)

1

On

2

Roughing (DYNROUGH)

0

Off

1

On

3

Semi-finishing (DYNSEMIFIN)

0

Off

1

On

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Continuous-path mode, exact stop, LookAhead

6.3 Continuous-path mode

Index <n>

Dynamic response mode

<Value>

Free-form surface mode: Extension

function

4

Finishing (DYNFINISH)

0

Off

1

On

5

Smooth-finishing (DYNPREC)

0

Off

1

On

The "Free-form surface mode: Extension function" is typically only active if the "Free-form

surface mode: Basic functions" are also active. Therefore, the settings in

MD20443 $MC_LOOKAH_FFORM[<n>] should correspond to the settings in

MD20606 $MC_PREPDYN_SMOOTHING_ON[<n>].

The standard Look Ahead functionality is active in the dynamic response modes in which the

"Free-form surface mode: Extension function" is switched off.

Programming

Generally speaking, the "Free-form surface mode: Extension function" becomes effective as a

result of a change in the dynamic response mode in the part program.

Example

The following parameters are assumed:

MD20443 $MC_LOOKAH_FFORM[0] = 0

MD20443 $MC_LOOKAH_FFORM[1] = 0

MD20443 $MC_LOOKAH_FFORM[2] = 1

MD20443 $MC_LOOKAH_FFORM[3] = 1

MD20443 $MC_LOOKAH_FFORM[4] = 1

MD20443 $MC_LOOKAH_FFORM[5] = 1

Change of the dynamic response mode in the part program:

Program code

Comment

N10 DYNPOS

; Activate DYNPOS dynamic response

mode.

Standard Look Ahead functionality is

active in the DYNPOS dynamic re-

sponse mode.

N100 G17 G54 F10000

N101 DYNFINISH

; Activate DYNFINISH dynamic re-

sponse mode.

The "Free-form surface mode: Exten-

sion functions" are active in the

DYNFINISH dynamic response mode.

N102 SOFT G642

N103 X-0.274 Y149.679 Z100.000 G0

N104 COMPCAD

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6.4 Dynamic adaptations

Note

The smoothing of the path velocity does not lead to contour errors.

Variations in axis velocity due to curvatures in the contour at constant path velocity may

continue to occur and are not reduced with this function.

Variations in path velocity due to the input of a new feedrate are not changed either. This

remains the responsibility of the programmer of the subprogram.

Requirements

• The smoothing of the path velocity is only effective in continuous-path mode with

LookAhead over multiple blocks with SOFT and BRISK. Smoothing is not effective with G0.

• The controller's cycle times must be configured in such a way that preprocessing can prepare

sufficient blocks to enable an acceleration process to be analyzed.

Activation/deactivation

The "smoothing of the path velocity" function is activated/deactivated with the machine data:

MD20460 $MC_LOOKAH_SMOOTH_FACTOR (smoothing factor for LookAhead)

Value

Meaning

0.0

Smoothing of the path velocity not active (default)

> 0

Smoothing of the path velocity active

A change in the MD setting is only made effective through NEW CONF.

Parameterization

Smoothing factor

The smoothing factor is set via the channel-specific machine data:

MD20460 $MC_LOOKAH_SMOOTH_FACTOR (smoothing factor for LookAhead)

The percentage value defines how much longer a processing step without accelerations/

decelerations may be than the corresponding step with accelerations/decelerations.

This would be a "worst-case" value, if all accelerations within the part program, except the initial

approach motion, were smoothed. The actual extension will always be smaller, and may even be

0, if the criterion is not met by any of the accelerations. Values between 50 and 100% may also

be entered without significantly increasing the machining time.

Consideration of the programmed feed

The path velocity can be smoothed with or without taking the programmed feedrate into

consideration. The selection is made via the machine data:

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Continuous-path mode, exact stop, LookAhead

6.4 Dynamic adaptations

MD20462 $MC_LOOKAH_SMOOTH_WITH_FEED (path smoothing with programmed feedrate)

Value

Meaning

0

Programmed feedrate is not taken into consideration.

1

Programmed feedrate is considered (default setting).

When considering the programmed feedrate, the specified smoothing factor (see MD20460) is

maintained better when the override is 100%.

Axis-specific limit frequencies

The axis-specific limit frequencies are defined via the machine data:

MD32440 $MA_LOOKAH_FREQUENCY (smoothing frequency for LookAhead)

Acceleration and deceleration processes, which run with a high frequency, are smoothed

depending upon the parameterization of the following machine data or else are reduced in

dynamics:

MD20460 $MC_LOOKAH_SMOOTH_FACTOR (smoothing factor for LookAhead)

MD20465 $MC_ADAPT_PATH_DYNAMIC (adaptation of the dynamic path response)

For further information on MD20465, see Section "Adaptation of the dynamic path response

(Page 475)".

Note

If vibrations are generated in the mechanical system of an axis and if the corresponding

frequency is known, MD32440 should be set to a value smaller than this frequency.

The needed resonance frequencies can be calculated using the built-in measuring functions.

Mode of operation

The minimum value for MD32440 is calculated as f_path on the basis of the axes involved in the

path. For the smoothing only those acceleration processes are taken into consideration, in

which the start and the end velocity of this motion are reached within the time given below:

t = t₂ - t₁ = 2 / f_path

These acceleration processes are dispensed with if the resulting extension in the processing time

does not exceed the limit specified in excess of the smoothing factor (MD20460).

Example

The following parameters are assumed:

MD20460 $MC_LOOKAH_SMOOTH_FACTOR = 10%

MD32440 $MA_LOOKAH_FREQUENCY[AX1] = 20 Hz

MD32440 $MA_LOOKAH_FREQUENCY[AX2] = 20 Hz

MD32440 $MA_LOOKAH_FREQUENCY[AX3] = 10 Hz

The path involves the three axes X = AX1, Y = AX2, Z = AX3.

Basic functions

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Continuous-path mode, exact stop, LookAhead

6.4 Dynamic adaptations

The minimum value of MD32440 for these three axes is thus 10 Hz. This means that any

acceleration, which is completed within a period of t₂ - t₁ = 2/10 Hz = 200 ms, is examined. The

time t₂ is the time it takes to reach velocity v₁ again following an acceleration process starting

from velocity v₁. The extending of the execution time is also only considered within this range.

If the time t₂ - t₁ is greater than 200 ms or if the additional program execution time t₃ - t₂ is more

than 10% (= MD20460) of t₂ - t₁, the following time characteristic applies:

9

Y

Y

W

W

W

Figure 6-7

Characteristic of time-optimum path velocity (without smoothing)

If, however, the time t₂ - t₁ is less than 200 ms or if the additional program execution time t₃ - t₂

is no more than 10% of t₂ - t₁, the following time characteristic applies:

9

Y

Y

W

W

W

W

Figure 6-8

Characteristic of the smoothed path velocity

6.4.2

Adaptation of the dynamic path response

Function

Highly dynamic acceleration and deceleration processes during machining can cause excitation

of mechanical vibrations of machine elements and consequently a reduction of the surface

quality of the workpiece.

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Continuous-path mode, exact stop, LookAhead

6.4 Dynamic adaptations

The dynamic response of the acceleration and deceleration processes can be adapted to the

machine conditions using the "adaptation of the dynamic path response" function.

Note

The "adaptation of the dynamic path response" function only concerns the resulting path and

not the deceleration and acceleration processes of the individual axes involved in the path. For

this reason, critical deceleration and acceleration processes of the axes with respect to the

excitation of mechanical vibrations can occur due to discontinuous contour profiles or kinematic

transformations, even with a constant path velocity profile.

Effectiveness

The "adaptation of the dynamic path response" function is only effective during path motions:

• Continuous-path mode (G64, G64x)

In continuous-path mode, the optimal effect of the dynamic response adaptation is attained

with an active 100% override. Considerable deviations from this value or functions that cause

the path axes to decelerate (e.g. auxiliary function outputs to the PLC) greatly reduce the

desired action.

• Exact stop (G60)

In addition, the "adaptation of the dynamic path response" function is not active during path

motions:

• Programmed rapid traverse (G0)

• Changes in the override value

• Stop requests during motion (e.g. NC Stop, NC Reset)

• "Velocity-dependent path acceleration" function (DRIVE) is active

Activation/deactivation

The function is activated/deactivated with the machine data:

MD20465 $MC_ADAPT_PATH_DYNAMIC (adaptation of the dynamic path response)

Value

Meaning

= 1.0

Dynamic adaptation not active (default setting)

> 1.0

Dynamic adaptation active

When activation takes place, the "smoothing the path velocity" function is always activated

internally in continuous-path mode as well (see Section "Smoothing of the path velocity

(Page 472)").

If the smoothing factor (MD20460 $MC_LOOKAH_SMOOTH_FACTOR) is set to 0% (= function

deactivated; default!), a smoothing factor of 100% is used as a substitute. For a smoothing factor

other than 0%, the set value takes effect.

Basic functions

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6.4 Dynamic adaptations

Y_%

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Y

WDGDSW

WDGDSW

WDGDSW

W

W

W

W

W

W

W

W

W

Y_%

WDGDSW

Y

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WDGDSW

W

W

W

W

W

W

W

W

W

Figure 6-9

Path velocity profile optimized for time without smoothing or dynamic adaptation response

Y_%

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Y

WDGDSW

WDGDSW

W

W

W

W

W

W

W

W

W

Figure 6-10

Path velocity profile with adaptation of dynamic path response

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Continuous-path mode, exact stop, LookAhead

6.4 Dynamic adaptations

Intervals t

0

- t₁ and t₂ - t₃:

The acceleration process between t₀ - t₁ and the deceleration

process between t₂ - t₃ are extended in terms of time to t_adapt01

or t_adapt23 as a result of the acceleration being adapted.

Interval t₄ - t₅:

The acceleration process between t₄ - t₅ is executed with an

acceleration reduced by the maximum adaptation factor of

1.5. However, the acceleration process is completed before

time t_adapt45.

Interval t₆ - t₇:

The deceleration process between t₆ - t₇ remains unchanged as

it lasts longer than t_adapt67.

6.4.3

Determination of the dynamic response limiting values

In addition to determining the natural frequency of the path axes for assigning parameters to the

axis-specific limit frequencies (MD32440 $MA_LOOKAH_FREQUENCY), the implementation of

the "adaptation of the dynamic path response" function also requires dynamic response limits to

be determined for velocity, acceleration and jerk.

Procedure

The determination of the dynamic response limits for the traversing of path axes by means of

acceleration with jerk limiting (SOFT) is described below. This procedure can be applied by

analogy to the case of acceleration without jerk limiting (BRISK).

1. Deactivate the "adaptation of the dynamic path response" function:

MD20465 $MC_ADAPT_PATH_DYNAMIC[1] = 1

2. Observe the positioning behavior of each path axis at different traversing velocities. When

doing so, set the jerk such that the desired positioning tolerance is maintained.

Note

The higher the traversing velocity from which the positioning process is started, the higher

in general the jerk can be set.

3. Use the maximum permissible jerk determined for the least critical traversing velocity:

MD32431 $MA_MAX_AX_JERK (maximum jerk)

4. Determine the F_APD factor for all of the path axes using:

F_APD = (largest determined jerk) / (smallest determined jerk)

Note

The smallest determined jerk is the value for the jerk during the most critical traversing

velocity.

5. Enter the largest F_APD factor that was determined via all the path axes as the value for the

adaptation factor for the path dynamic response:

MD20465 $MC_ADAPT_PATH_DYNAMIC[ 1 ] = F_APD

Basic functions

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