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FANUC Series 30i/300i/300is-MODEL A. Machining Center System. User's manual - page 98

21.AXIS CONTROL FUNCTIONS

PROGRAMMING

B-63944EN/03

- 740 -

NOTE

1 If bit 0 (HBR) of parameter No. 7700 is set to 1,

EGB synchronization will not be canceled due to a
reset. Usually, set this parameter bit to 1.

2 In synchronous mode, it is not possible to specify

G27, G28, G29, G30, G30.1, and G53 for a slave
axis.

3 It is not possible to use controled axis detach for a

slave axis.

4 During synchronization, manual handle interruption

can be performed on the slave and other axes.

5 In synchronization mode, no inch/metric conversion

commands (G20 and G21) cannot be issued.

6 In synchronous mode, only the machine

coordinates on a slave axis are updated.

7 If bit 0 (EFX) of parameter No. 7731 is 0, no drilling

canned cycle can be used. To use a drilling canned
cycle, set bit 0 (EFX) of parameter No. 7731 to 1
and use G81.4 instead of G81 and G80.4 instead
of G80.

8 If TDP, bit 0 of parameter No. 7702, is 1, the

permissible range of T is 0.1 to 100 (1/10 of the
specified value).

9 If, at the start of EGB synchronization (G81), L is

specified as 0, synchronization starts with L
assumed to be 1 if bit 3 (LZR) of parameter
No.7701, is 0; if bit 3 (LZR) of parameter No.7701,
is 1, synchronization is not started with L assumed
to be 0. At this time, helical gear compensation is
performed.

10 Feed per revolution is performed on the feedback

pulses on the spindle. By setting ERV, bit 0 of
parameter No. 7703, to 1, feed per revolution can
be performed based on the speed on the
synchronous slave axis.

11 Actual cutting feedrate display does not take

synchronization pulses into consideration.

12 For an EGB slave axis, synchronous and

cpmposite control cannot be executed.

13 In EGB synchronization mode, AI contour control

mode is temporarily canceled.

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PROGRAMMING

21.AXIS CONTROL FUNCTIONS

- 741 -

- Helical gear compensation

For a helical gear, the workpiece axis is compensated for the
movement along the Z-axis (axial feed axis) based on the torsion angle
of the gear.
Helical gear compensation is performed with the following formulas:

Compensation angle =

360 (for metric input)

Compensation angle =

360 (for inch input)

where

Compensation angle: Signed absolute value (deg)

Z : Amount of travel on the Z-axis after the specification of G81
P : Signed gear helix angle (deg)

: Circular constant

T : Number of teeth
Q : Module (mm) or diametral pitch (inch

-1

)

Use P, T, and Q specified in the G81 block.

In helical compensation, the machine coordinates on the workpiece
axis and the absolute coordinates are updated with helical
compensation.

sin(P)

21.AXIS CONTROL FUNCTIONS

PROGRAMMING

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- 742 -

- Direction of helical gear compensation

The direction depends on HDR, bit 2 of parameter No. 7700.

When HDR is set to 1.

C:+, Z:+, P:+

Compensation direction : +

(a)

C:+, Z:+, P:-

Compensation direction : -

(b)

C:+, Z:-, P:+

Compensation direction : -

(c)

C:+, Z:-, P:-

Compensation direction : +

(d)

C:-, Z:+, P:+

Compensation direction : -

(e)

C:-, Z:+, P:-

Compensation direction : +

(f)

C:-, Z:-, P:+

Compensation direction : +

(g)

C:-, Z:-, P:-

Compensation direction : -

(h)

When HDR is set to 0. (In (a), (b), (c), and (d), the same as that if HDR is 1)

-Z

C:-, Z:+, P:+

Compensation direction : +

(e)

C:-, Z:+, P:-

Compensation direction : -

(f)

C:-, Z:-, P:+

Compensation direction : -

(g)

C:-, Z:-, P:-

Compensation direction : +

(h)

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PROGRAMMING

21.AXIS CONTROL FUNCTIONS

- 743 -

- Synchronization coefficient

A synchronization coefficient is internally represented using a fraction
(Kn/Kd) to eliminate an error. The formula below is used for
calculation.

coefficien

ation

Synchroniz

where
L : Number of hob threads
T : Number of teeth

Number of pulses of the position detector per rotation about the
master axis (parameter No. 7772)

Number of pulses of the position detector per rotation about the
slave axis (parameter No. 7773)

Kn / Kd is a value resulting from reducing the right side of the above
formula, but the result of reduction is subject to the following
restrictions:
-2147483648

≤

2147483647

≤

65535

When this restriction is not satisfied, the alarm PS1596 is issued when
G81 is specified.

Example

O1000 ;
N0010 M19 ;

Tool axis orientation

N0020 G28 G91 C0 ; Reference position return on the

workpiece axis

N0030 G81 T20 L1 ; Synchronous start on tool and

workpiece axes

(Rotation about the workpiece axis by
18

per rotation about the tool axis)

N0040 S300 M03 ;

Rotation about the tool axis at 300min

-1

N0050 G01 X F ;

Movement along the X-axis (cut)

N0060 G01 Z F ;

Movement along the Z-axis
(machining)

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

If necessary, axis commands such as C,
X, and Z commands are allowed.

N0100 G01 X F ;

Movement along the X-axis (escape)

N0110 M05 ;

Stop on the tool axis

N0120 G80 ;

Synchronous cancellation on tool and
workpiece axes

N0130 M30 ;

21.AXIS CONTROL FUNCTIONS

PROGRAMMING

B-63944EN/03

- 744 -

- Retract function

(1) Retract function with an external signal

When the retract switch on the machine operator’s panel is
turned on, retraction is performed with the retract amount set in
parameter No. 7741 and the feedrate set in parameter No. 7740.
No movement is performed along an axis for which 0 is set as the
retract amount.
For the retract switch, refer to the relevant manual provided by
the machine tool builder.

(2) Retract function with an alarm

If, during EGB synchronization or automatic operation, a CNC
alarm is issued, retraction is performed with the retract amount
set in parameter No. 7741 and the speed set in parameter No.
7740.
This can prevent the tool and the object being machined from
damage if a servo alarm is generated.

No movement is performed along an axis for which 0 is set as the
retract amount.
For the retract switch, refer to the relevant manual provided by
the machine tool builder.

Conditions under the retract function with an alarm can be
executed
The conditions under which the retract function with an alarm
can be executed can be changed using the settings of ARE, bit 1
of parameter No. 7703, and bit 2 (ARO) of parameter No. 7703.
The table below lists parameter settings and corresponding
conditions.

ARE ARO

Condition

EGB synchronization is in progress.

1 1

Both EGB synchronization and
automatic operation are in progress.

0 0
0 1

Either EGB synchronization or
automatic operation is in progress.

CAUTION

1 Retraction is performed at the speed specified in

parameter No. 7740.

2 Feed hold is not effective to movement during

retraction.

3 Feedrate override is not effective to movement

during retraction.

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PROGRAMMING

21.AXIS CONTROL FUNCTIONS

- 745 -

NOTE

1 During a retract operation, an interlock is effective

to the retract axis.

2 During a retract operation, a machine lock is

effective to the retract axis.

3 The retraction direction depends on the movement

direction of the machine, regardless of whether an
mirror image (signal and setting) is enabled or
disabled. (No mirror image can be applied to the
updating of absolute coordinates.)

4 If retraction is performed during automatic

operation, automatic operation is halted
simultaneously with a retract operation, but it is at
the end of the retract operation that the operation
state switches to the automatic operation halt state.

5 It is not possible to perform automatic operation

during retraction.

6 The acceleration/deceleration of a retract operation

is in the acceleration/deceleration state at the start
of retraction.

7 Retract movement is performed with non-linear

type positioning.

8 If, during a retract operation, a reset or an

emergency stop is made, the operation is
interrupted.

9 If, during a retract operation on multiple axes, an

OT alarm or a malfunction prevention alarm is
issued for a retract axis, the operation stops only
on the axis for which the alarm is issued if bit 4
(RTS) of parameter No. 7731 is 0. If bit 4 (RTS) of
parameter No. 7731 is 1, the retract operation is
interrupted on all axes. If a servo alarm or non-axis
malfunction prevention alarm is issued, the retract
operation is interrupted on all axes regardless of
the setting of bit 4 (RTS) of parameter No. 7731.

10 To enable the retract function with an alarm, bit 3

(ART) of parameter No.7702, must be set.

11 The retract function with an alarm does not perform

a retract operation on the retract axis if an overtravel
alarm or a servo alarm is geneated on the retract
axis.

12 If a new alarm is issued during retraction with the

retract function with an alarm, a retract operation is
not performed.

21.AXIS CONTROL FUNCTIONS

PROGRAMMING

B-63944EN/03

- 746 -

21.7.2

Electronic Gear Box Automatic Phase Synchronization

Overview

In the electronic gear box (EGB), when synchronization start or
cancellation is specified, synchronization is not started or canceled
immediately. Instead, acceleration/deceleration is executed first.
Therefore, synchronization can be started or canceled while the
spindle is rotating.    Also, synchronization ratio can be changed while
the spindle is rotating.
At synchronization start, automatic phase synchronization is
performed such that the workpiece axis position matches the position
corresponding to the spindle one-rotation signal. With this
synchronization, the same operation is performed as synchronization
start caused by a one-rotation signal in hobbing synchronization when
using the functions of a hobbing machine.
The spindle corresponds to the EGB master axis and the workpiece
axis corresponds to an EGB slave axis.

Format
- Acceleration/deceleration type

G81 T _ L _ R1 ;

Synchronization start

G80 R1 ;

Synchronization cancellation

T :

Number of teeth (range of valid settings: 1-1000)

L :

Number of hob threads (range of valid settings: -200 to
+200, excluding 0)

When L is positive, the direction of rotation about the
workpiece axis is positive (+ direction).

When L is negative, the direction of rotation about the
workpiece axis is negative (- direction).

- Acceleration/deceleration plus automatic phase synchronization type

G81 T _ L _ R2 ;

Synchronization start

G80 R1 ;

Synchronization cancellation

T :

Number of teeth (range of valid settings: 1-1000)

L :

Number of hob threads (range of valid settings: -200 to
+200, excluding 0)

When L is positive, the direction of rotation about the
workpiece axis is positive (+ direction).

When L is negative, the direction of rotation about the
workpiece axis is negative (- direction).

B-63944EN/03

PROGRAMMING

21.AXIS CONTROL FUNCTIONS

- 747 -

Explanation
- Acceleration/deceleration type

Synchronization

cancellation command

Synchronization

start command

Workpiece-

axis speed

Synchronization state

Acceleration

Deceleration

Spindle

speed

1. Specify G81R1 to start synchronization.

When G81R1 is specified, the workpiece axis (slave axis) is
subject to acceleration at the acceleration rate set in parameter No.
7778. When the synchronization speed is reached, the G81R1
block is terminated.

2. For cancellation, specify G80R1 while the tool is moved away

from the workpiece.

3. When G80R1 is specified, deceleration is started immediately at

the acceleration rate set in parameter No. 7778.
When the speed is reduced to 0, the G80R1 block is terminated.

NOTE

1 During synchronization start/cancellation,

acceleration/deceleration is linear.

2 In the automatic cancellation of synchronization due

to one of the following causes, deceleration is
performed and synchronization is canceled:
<1> Reset
<2> PW0000 (POWER MUST BE OFF)
<3> IO alarm

3 If EFX, bit 0 of parameter No. 7731, is 0, the

canned cycle for drilling cannot be used. To use
the canned cycle for drilling, set EFX, bit 0 of
parameter No. 7731, to 1 and use G81.4 instead of
G81 and G80.4 instead of G80.

Content .. 96 97 98 99 ..