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FANUC Series 0i-MODEL F Plus. CONNECTION MANUAL (FUNCTION) - page 38

1. AXIS CONTROL

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CAUTION

1 Feed hold, interlock, and machine lock are invalid to a slave axis in EGB

synchronization.

2 Even if an OT alarm is issued for a slave axis in EGB synchronization,

synchronization will not be canceled.

3 During synchronization, it is possible to execute a move command for a slave

axis and other axes, using a program. The move command for a slave command
must be an incremental one.

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 synchronization mode, it is not possible to specify G27, G28, G29, G30, and

G53 for a slave axis.

3 It is not possible to use controlled 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 synchronization mode, only the machine coordinates on a slave axis are

updated.

7 If bit 0 (EFX) of parameter No. 7731 is 0, no canned cycle for drilling can be

used. To use a canned cycle for drilling, 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 bit 0 (TDP) of parameter No. 7702 is 1, the permissible range of T is 0.1 to 500

(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 bit 0 (ERV) 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 composite control cannot be executed.
13 In EGB synchronization mode, AI contour control mode is temporarily canceled.
14 Not advanced preview feed-forward but conventional feed-forward is enabled in

the path where EGB synchronization mode is effective.

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Synchronization start/cancellation timing chart example

Fig. 1.9.1 (b)

How to reduce the synchronous error

When you use the Electronic gear box function, to reduce the synchronous error, please apply
feed-forward to the slave axis and set 100% to the parameter of feed-forward coefficient.
And please confirm the effectiveness of feed-forward by the following procedure.

[Procedure]

When the slave axis synchronizes only with the command from master axis (i.e. When the slave
axis doesn’t use helical gear compensation), the position error of slave axis is regarded as the
synchronous error. Please check that the position error (DGN data No.300) of the slave axis
becomes 0 or so.

And also please check the position error is near 0 even when the speed of the master axis is
changed.

Please set the following parameters to use Feed-forward function with 100% coefficient.

[Setting parameters]
Bit 3 (PIEN) of parameter No. 2003 = 1 (Slave axis)

Use PI control in velocity control

Bit 1 (FEED) of parameter No. 2005 = 1 (Slave axis)

Use Feed-forward function

Bit 1 (FFALx) of parameter No. 2011 = 1 (Slave axis)

Use Feed-forward function irrespective
of feed mode

Parameter No.2068 (FF coefficient) = 10000 (Slave axis) Feed-forward coefficient is 100%.

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Please refer to the chapter of “Feed-forward Function” in FANUC AC SERVO MOTOR

series

FANUC AC SERVO MOTOR

series FANUC LINEAR MOTOR L

S series FANUC

SYNCHRONOUS BUILT-IN SERVO MOTOR D

S series Parameter manual (B-65270EN) about the

detail of Feed-forward function.

How to reduce shock at the start of acc./dec.

If the shock of slave axis is large when the master axis accelerates or decelerates in velocity control mode,
please apply “Soft start/stop” function to the master axis (spindle axis).
Please set the following parameters to use Soft start/stop function.

[Setting parameters]

Bit 2 (SOSALWs) of parameter No. 4399 = 1 Use Soft start/stop function even at emergency stop
Note) If the spindle axis is a sub axis of spindle switching control, please set bit 2 of parameter No.

4472 instead of bit 2 of parameter No. 4399.

Parameter No. 4030

Soft start/stop setting time

Parameter No. 4508

Rate of change in acceleration at soft start/stop

Note) Parameters Nos. 4030 and 4508 should be tuned according to the spindle characteristic to

reduce the shock well.

[Signals]

Soft start/stop signal SOCNA <Gn071.4> : First spindle
Soft start/stop signal SOCNB <Gn075.4> : Second spindle
Soft start/stop signal SOCNC <Gn205.4> : Third spindle
Soft start/stop signal SOCND <Gn267.4> : Fourth spindle

Please refer to FANUC AC SPINDLE MOTOR

series BUILT-IN SPINDLE MOTOR B

series

parameter manual (B-65280EN) about the detail of Soft start/stop function.

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 =

sin(P)

360 (for metric input)

Compensation angle =

sin(P)

360 (for inch input)

where

Compensation angle: Signed absolute value (deg)
Z

Amount of travel on the Z-axis after the specification of G81

Signed gear helix angle (deg)

Circular constant

Number of teeth

Module (mm) or diametral pitch (inch

-1

)

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

In helical gear compensation, the machine coordinates on the workpiece axis and the absolute coordinates
are updated with helical gear compensation.
The updated timing is as follows.

Machine coordinates

Absolute coordinates

During helical gear compensation

Bit 7(HAD) of parameter No.7731

= 0

= 1

Synchronization cancel

During helical gear compensation

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Direction of helical gear compensation

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

When HDR = 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 : +

C : Compensation direction:-

(e)

C : -, Z : +, P : -

Compensation direction:+

(f)

C : -, Z : -, P : +

Compensation direction:+

(g)

C : -, Z : -, P : -

Compensation direction:-

(h)

When HDR = 0 ((a), (b), (c), and (d) are the same as when HDR = 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)

Fig. 1.9.1 (c) Direction of helical gear compensation

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

≤

2147483647

When this restriction is not satisfied, the alarm PS1596, “EGB OVERFLOW” is issued when G81 is
specified.

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Retract function

(1) Retract function with an external signal

When the retract signal, RTRCT<Gn066.4>, becomes “1” (the rise of the signal is captured),
retraction is performed with the retract amount set in parameter No. 7741 and the speed set in
parameter No. 7740.
No movement is performed along an axis for which 0 is set as the retract amount.
After the end of retraction, the retract completion signal, RTRCTF<Fn065.4>, is output.

(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.
After the end of retraction, the retract completion signal, RTRCTF, is output.

Conditions under the retract function with an alarm

The conditions under which the retract function with an alarm can be changed using the settings of
bit 1 (ARE) 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.

Both EGB synchronization and automatic operation are in progress.

Either EGB synchronization or automatic operation is in progress.

Timing chart

<1> On/off timing of RTRCT and RTRCTF

RTRCT

RTRCTF

Movement

Move

Retract operation

Move

command

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<2> Interruption of retraction with to a reset

RTRCT

RTRCTF

Movement

Interruption of

retract operation

RST

Turn off the RTRCT signal simultaneously with turning on of

the RST signal.

<3> Interruption of retraction due to an emergency stop

RTRCT

RTRCTF

Movement

Interruption of

retract operation

*ESP

Turn off the RTRCT signal simultaneously with turning off of

the *ESP signal.

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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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. The

retract operation terminates in the machine lock state, and a retract completion
signal is output.

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.

Automatic operation start signal
(STL)

Automatic operation halt signal
(SPL)

Automatic operation signal

(OP)

Automatic operation

Retract operation

Start

Command interruption

Fig. 1.9.1 (d)

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. At this time, the retract completion signal does not
become “1”.

9 To enable the retract function with an alarm, bit 3 (ART) of parameter No.7702

must be set.

10 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 generated on the retract
axis.

11 If a new alarm is issued during retraction with the retract function with an alarm,

a retract operation is not performed.

12 After the end of retraction with a servo alarm, servo position control stops in 400

ms.

13 The retract completion signal RTRCTF <Fn065.4> becomes “0” when a move

command is issued for any axis after retract operations on all axes are
completed.

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Example

O1000 ;
N0010 M19 ;

Tool axis orientation

N0020 G28 G91 C0 ;

Reference position return on the work axis

N0030 G81 T20 L1 ;

Start of synchronization of the tool axis and the work axis

(Rotation about the work 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 (cutting)

N0060 G01 Z_ F_ ;

Movement along the Z-axis (machining)

;

If required, C, X, Z, and other axis command are possible.

;

N0100 G01 X_ F_ ;

Movement along the X-axis (escape)

N0110 M05 ;

Stop on the tool axis

N0120 G80 ;

Cancellation of synchronization of the tool and work axes

N0130 M30 ;

Signal

Retract signal RTRCT <Gn066.4>

[Classification] Input signal

[Function] Performs retraction for the axis specified with a parameter.

[Operation] When this signal becomes “1”, the CNC operates as follows:

The CNC can capture the rise of the signal and perform retraction for the axis for which

the retract amount has been specified with parameter No. 7741. The retract amount and
the retract speed will be the values previously set in parameters Nos. 7741 and 7740.
After the end of retraction, the retract completion signal, RTRCTF, is output. The retract
signal is effective both during automatic operation mode (MEM, MDI, etc.) and manual
operation mode (HNDL, JOG, etc.). If, during automatic operation, the retract signal is
set to “1”, a retract operation is performed and, at the same time, automatic operation is
halted.

Retract completion signal RTRCTF <Fn065.4>

[Classification] Output signal

[Function] Posts notification of the completion of retraction.

[Operation] This signal is set to “1” in the following case:

Upon the completion of retraction (at the end of movement)

This signal is set to “0” in the following case:
-

When a move command is issued for any retract axis after the end of a retract
operation.

NOTE

The retract signal is not accepted while the retract completion
signal is set to “1”.

EGB mode signal SYNMOD <Fn065.6>

[Classification] Output signal

[Function] Posts notification that synchronization using the EGB is in progress.

[Operation] This signal is set to “1” in the following case:

While synchronization using the EGB is in progress

This signal is set to “0” in the following case:
-

Once synchronization using the EGB has terminated

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