FANUC Series 0i-MODEL F Plus. CONNECTION MANUAL (FUNCTION) - page 30

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1.6.5

Synchronization Establishment

Explanation

Upon power-up or after emergency stop cancellation, the machine positions on the master axis and slave
axis under axis synchronous control are not always the same. In such a case, the synchronization
establishment function adjusts the machine position on the slave to that on the master axis.

Synchronization establishment method

The method of synchronization establishment differs whether the synchronization error compensation is
performed or not. For the synchronization establishment when synchronous error compensation is
performed, see Subsection “Synchronization Error Compensation”.

- Synchronization establishment based on machine coordinates

To perform synchronization establishment, enable synchronization establishment based on machine
coordinates by setting bit 7 (SOFx) of parameter No. 8303 to 1.
This synchronization establishment is performed by outputting the machine  coordinate difference
between the master axis and slave axis as command pulses for the slave axis. Thus, the position of the
master axis and the slave axis become the same. A maximum allowable compensation value to be used
for synchronization establishment is the value in parameter No. 8325. As a maximum allowable
compensation value, set a maximum allowable value by which the machine may move abruptly.
If a compensation value is larger than the value set in this parameter, an alarm SV0001,  “SYNC
ALIGNMENT  ERR” is issued, and synchronization establishment is not performed. Moreover, when
parameter No. 8325 is set to 0, synchronization establishment is not performed.
The result of comparing the positional difference between the master axis and slave axis with a maximum
allowable compensation value for synchronization establishment can be checked using the
synchronization establishment enable state output signals SYNOF1 to SYNOF8 <Fn211>.

- First synchronization establishment after power-up

In the first synchronization establishment after power-up, there are a method by the manual reference
position return and other methods.

Synchronization establishment based on manual reference position return
operation

When manual reference position return operation is performed along axes under axis synchronous control,
the machine is placed at the reference position on the master axis and slave axis according to the same
sequence as for normal reference position return operation. Therefore, when the grid position of the
master axis and the slave axis shifts and the shift amount is not set to parameter No.8326, the master axis
and the slave axis stop at each grid position. For details, see Subsection “Setting of grid position”.

Synchronization establishment except manual reference position return

In case of synchronization establishment by absolute position detection or except manual reference
position return, when the reference position is established, the synchronization establishment is performed
automatically.
When the position is set by the following functions, the synchronization establishment is executed.
- Temporary absolute coordinate setting
- Checking the stored stroke during the time from power–on to the reference position establishment

Synchronization establishment after emergency stop cancellation, etc.

Synchronization establishment is also performed when servo position control is turned on, for example, at
emergency stop cancellation, servo alarm cancellation, or servo-off cancellation .
However, when the controlled axes detach is canceled, the synchronization establishment is not
performed until the reference position is established by the manual reference position return etc.

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One-direction synchronization establishment

The synchronization establishment can be performed by setting bit 0 (SSO) of parameter No. 8305 to 1 to
move the machine in one direction along the master axis and slave axis. The move direction depends on
the reference position setting based on bit 0 (SSAx) of parameter No. 8304. When bit 0 (SSAx) of
parameter No. 8304 = 0, for example, the machine coordinate on the master axis or slave axis, whichever
larger, is used as the reference point. So, the machine moves in the + direction along the axes.
When bit 1 (SSE) of parameter No. 8305 is set to 1, normal synchronization establishment is performed
instead of one-direction synchronization establishment after an emergency stop.

Axis movement in synchronization establishment

A machine coordinate difference between the master axis and slave axis is output at a time as command
pulses, when bit 0 (SJR) of parameter No. 8306 is 0. So, if the compensation value is large, the machine
abruptly makes a large movement.
When bit 0 (SJR) of parameter No. 8306 = 1 and one-direction synchronization establishment is invalid
(bit 0 (SSO) of parameter No. 8305 = 0), the axis movement of the synchronization establishment in the
axis synchronous control can be executed with the feedrate of manual rapid traverse and
acceleration/deceleration after interpolation in rapid traverse. In the synchronization establishment using
this function, the setting values used for manual rapid traverse and acceleration/deceleration after
interpolation in rapid traverse are the parameter values set with slave axis.
The followings are the parameters related to this function.

•

No.1424

:Manual rapid traverse rate for each axis (When 0 is set, the rate set in parameter No.

1420)

•

No.1620

:Time constant used for linear acceleration/deceleration for each axis

•

No.1621

:Time constant T2 used for bell-shaped acc./dec. in rapid traverse for each axis

•

No.1401#1 :Positioning (G00) is performed with non-linear or linear interpolation

•

No.1603#4 :Acceleration/deceleration used for positioning of linear interpolation type is

acceleration fixed or time fixed type

WARNING

1 Do not execute automatic or manual operation while the axes are moving for the

synchronization establishment.

2 Do not use other function while the axes are moving for the synchronization

establishment.

3 Do not change operation mode while the axes are moving for the synchronization

establishment.

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NOTE

1 For the axes engaged in the synchronization establishment, the signals below are

invalid:

•

Rapid traverse override

•

External deceleration

•

Dry run

•

Interlock

2 When the one-direction synchronization establishment function under axis

synchronous control is valid (bit 0 (SSO) of parameter No.8305 is set to 1), this
function is disabled, regardless of bit 0 (SJR) of parameter No. 8306

3 When the reference position has not been established, the synchronization

establishment based on machine coordinates is not executed.

4 When the stored stroke limit check immediately after power-on is enabled (Bit 0

(DOT) of parameter No. 1311 = 1), the synchronization establishment based on
machine coordinates is executed as follows.
- Bit 6 (LZR) of parameter No. 1300 = 0 : It is executed after power-on.
- Bit 6 (LZR) of parameter No. 1300 = 1 : It is executed after reference position

establishment.

1.6.6

Synchronization Error Check

1.6.6.1

Synchronization error check

A synchronization error amount is monitored at all times. If the error amount exceeds a certain limit, an
alarm is issued and the movement along the axis is stopped. For the synchronization error check when
synchronous error compensation is performed, see Subsection “Synchronization Error Compensation”.

Synchronization error check based on machine coordinates

When the value other than 0 is set in parameter No.8314, a synchronization error check based on machine
coordinates is enabled.
The machine coordinate on the master axis is compared with that on the slave axis. When the error
between the machine coordinates exceeds the value set in parameter No. 8314, the alarm  SV0005,
“SYNC EXCESS ERR (MCN)” is issued, and the motor is stopped immediately.  The alarm  SV0005 is
output to both the master axis and the slave axis.
This synchronization error check can  also be made in the emergency stop, servo-off, and servo alarm
state.
If a synchronization error check is made when the mode of operation is switched between synchronous
operation and normal operation with an input signal, an error check is made even in normal operation. So,
even if the axis synchronous control selection signal (SYNC) or the axis synchronous control manual feed
selection signal (SYNCJ) is set to “0” by mistake during synchronous operation, damage to the machine
can be prevented.
The machine coordinates on the master axis and slave axis can be checked using the machine coordinate
match state output signals SYNMT1 to SYNMT8 <Fn210>.

Synchronization error check based on a positional deviation value

When the value other than 0 is set in parameter No.8323, a synchronization error check based on a
positional deviation value is enabled. The servo positional deviation value of the master axis and slave
axis is monitored during axis synchronous control. When the positional deviation value exceeds the limit
value set in parameter No. 8323, the alarm DS0001, “SYNC EXCESS ERR (POS DEV)” is issued, and
the axis synchronous control positional deviation error alarm signal SYNER<Fn403.0> is output.
The alarm DS0001 is issued to the master axis and slave axis.

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When bit 4 (SYA) of parameter No. 8301 is set to 0, the positional deviation limit value of the master axis
and slave axis is checked even if a servo-off occurs during axis synchronous control.

1.6.6.2

Methods of alarm recovery by synchronization error check

To recover from an alarm issued as a result of synchronization error check, the method is different by
setting parameter of bit 5 (SCAx) of parameter No.8304.

When the bit 5 (SCAx) of parameter No.8304 is set to 1

When the bit 5 (SCAx) of parameter No.8304 is set to 1 (synchronous operation is used at all times), a
synchronization error can be decreased by using the correction mode. When the correction mode is used,
synchronization error check can be temporarily disabled, and a movement can be made along the master
axis or slave axis to correct a synchronization error.
In the correction mode, synchronization error compensation and error check are not performed, so that an
alarm DS0003, “SYNCHRONIZE ADJUST MODE” is issued as a warning.
1.

Select the correction mode, and select an axis along which a movement is to be made by manual
feed of a master axis . Set bit 2 (ADJx) of parameter No. 8304 of the master axis or slave axis to 1 to
select the correction mode. Thus, by manual feed of a master axis , a movement can be made along
the axis with this parameter set to 1.

When this parameter is set to 1, the alarm DS0003 is issued.

Reset the synchronization error excessive alarm.

In this state, synchronization error compensation and error check are not performed. Be careful.

Select the manual mode (jog, incremental feed, or handle).

While checking the synchronization error amount, make a movement along the master axis or slave
axis in the direction that reduces the error.

If one master axis has multiple slave axes, an attempt to reduce the synchronization error of one
slave axis by master axis movement may increase the synchronization error of another slave axis,
thus a movement in any direction is disabled. In such a case, by setting bit 4 (MVBx) of parameter
No. 8304 to 1, a movement can be made in the direction that increases the synchronization error.

When the synchronization error is reduced to within the allowable value for suppressing the alarm,
reset the value of bit 2 (ADJx) of parameter No. 8304 to the original value to switch from the
correction mode to the normal synchronization mode.

Synchronization error compensation and synchronization error check are restarted.

Reset the correction mode alarm.

When the bit 5 (SCAx) of parameter No.8304 is set to 0

When the bit 5 (SCAx) of parameter No.8304 is set to 0 (synchronous operation and normal operation are
switched by using an input signal), a synchronization error can be decreased by using the normal
operation. Use the procedure below for recovery from alarm SV0005.
1.

Set signal SYNC/SYNCJ to “0” to select normal operation.

Set a value greater than the current value in the parameter No. 8314 for specifying a maximum
allowable synchronization error, then reset the alarm.

Make a movement along the master axis or slave axis by using the manual handle so that the
machine coordinates of the master axis and slave axis becomes almost the same.

Return the value of parameter No. 8314 for specifying a maximum allowable synchronization error
to the original value.

1.6.7

Axis Synchronous Control Torque Difference Alarm

Explanation

If a movement made along the master axis differs from a movement made along the slave axis during axis
synchronous control, the machine can be damaged. To prevent such damage, the torque command
difference between the two axes is observed. If the difference exceeds certain limit, a servo alarm
SV0420, ” SYNC TORQUE EXCESS” can be issued.

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[System configuration]

Slave axis
position
command

Alarm detection

Master axis
position
command

Position gain

Feedrate
control

Master axis
torque command

Master axis
position feedback

Torque command
difference

Compare absolute
value with threshold

Feedrate
control

Slave axis torque
command

Slave axis position feedback

Position gain

Fig. 1.6.7 (a) System configuration

[Method of use]

Specify the threshold parameter No. 2031 according to the procedure below.
1.

Set 14564 in parameter No. 2031.

Display the diagnostic screen by pressing the function key

then the soft key [DIAGNOSIS].

Diagnosis data No. 3506 indicates the absolute value of the torque difference between the two axes.

Read the absolute torque difference value presented when normal operation is being performed. In
the threshold parameter No. 2031, set a value obtained by adding some margin to the read absolute
value.

An absolute torque difference value can be read using SERVO GUIDE Mate.

Enabling/disabling of alarm detection

Alarm detection is enabled when the time set in parameter No. 8327 has elapsed after the servo ready
signal SA <Fn000.6> is set to “1”. When the signal for disabling torque difference alarm detection for
axis synchronous control NSYNCA <Gn059.7> is set to “1”, alarm detection is disabled.

SA<F000.6>

1
0

Alarm detection
function

Enabled

Disabled

Setting of parameter No. 8327
(512 msec when this parameter is not set)

Fig.1 .6.7 (b) Timing chart

When the servo ready signal SA <Fn000.6>is set to “0”, torque difference alarm detection is disabled.

NOTE

The servo axis number combination of the master axis and slave axis
synchronized with each other must be such that an odd servo axis number is
assigned to the master axis and the next servo axis number is assigned to the
slave axis like (1,2) or (3,4).

Parameter

2031

Torque command difference threshold of torque difference alarm

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[Input type] Parameter input

[Data type] Word axis

[Valid data range] 0 to 14564

If the absolute value of the torque command difference between two axes exceeds the
value set in this parameter, an alarm is issued.
Set the same value for two axes that are placed under axis synchronous control.
The servo axis numbers of the synchronized master axis and slave axis must be assigned
so that an odd number is assigned to the master axis and the next axis number is assigned
to the slave axis. Examples are (1,2) and (3,4).

Diagnosis data

3506

SYNC TORQUE DIFFERENCE

[Data type] Word axis

[Valid data range] 0 to 32767

The absolute torque difference value between the master axis and the slave axis in the
axis synchronous control is displayed.

1.6.8

Synchronization Error Compensation

Explanation

When a synchronization error amount exceeding the zero width set in parameter No. 8333 is detected,
compensation pulses for synchronization error reduction are calculated and added onto the command
pulses output for the slave axis. This compensation is not performed in servo-off state, servo alarm state,
follow-up operation, and correction mode.
Compensation pulses are calculated by multiplying the synchronization error amount between master and
slave axes by a compensation gain.

Compensation pulses = synchronization error

(Ci/1024)

Ci: Compensation gain (parameter No. 8334)

Compensation

pulse counter

Added to command for
slave axis

Master axis
machine position

Slave axis machine
position

Compensation gain

Compensation pulses

Synchronization
error counter

Fig. 1.6.8 (a) Compensation pulses

In case that the following parameters are set, after the reference position establishment had been
completed and the first synchronization establishment after power-up was performed, the synchronization
error counter is reset and the synchronization error compensation is started.

•

Bit3 (CLPx) of parameter No.8304 is set to 1.

•

Bit5 (SCAx) of parameter No.8304 is set to 1.

•

The value other than 0 is set in parameter No.8334

NOTE

If the positional deviation corresponding to the load were generated like a past
analog servo, this function was effective for decreasing the synchronization
error. When a current digital servo is applied, positional deviation corresponding
to the load are not generated. Therefore, the function need not be applied.

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Synchronization error compensation smooth suppress function

When bit 6 (SMSx) of parameter No. 8304 is set to 1, the synchronization error compensation smooth
suppress function is enabled. With this function, another set of parameters for a synchronization error
zero width and synchronization error compensation gain (B and Ks in the Fig.1.6.8 (b)) can be set. So,
even a small synchronization error can be reduced smoothly as shown below.

Synchronization error compensation gain

Synchronization error value

Fig. 1.6.8 (b) Smooth suppress function

A:  Synchronization error zero width (parameter No. 8333)
B:  Synchronization error zero width 2 (parameter No. 8335) (0 < B < A)
Kd:  Synchronization error compensation gain (parameter No. 8334)
Ks:  Synchronization error compensation gain 2 (parameter No. 8336) (0 < Ks < Kd)
Er:  Synchronization error amount between the current master axis and slave axis
K:  Current synchronization error compensation gain for Er

1.

When Er < B, compensation is not performed. (K = 0)

When B < Er < A
Compensation is performed with the following gain:

Ks +

(Er - B)(Kd - Ks)

A - B

When Er > A, compensation is performed with a gain of K = Kd.

Synchronization establishment

When synchronization error compensation is performed , synchronization establishment is performed in
the same way as synchronization error compensation. This means that the positional difference between
the master axis and slave axis is regarded as a synchronization error, and pulses produced by multiplying
the positional difference by a synchronization error compensation gain are output for the slave axis. So,
the parameter No. 8334 for specifying a synchronization error compensation gain must be set before
synchronization establishment can be performed.
If the parameter No. 8333 for specifying a synchronization error compensation zero width is set, no
further synchronization establishment is performed after the positional difference between the master axis
and slave axis becomes the zero width or below.
For “first synchronization establishment after power-up” and “synchronization establishment after
emergency stop cancellation, etc.”, see Subsection “Synchronization Establishment”.

Synchronization error check

When synchronization error compensation is performed, the synchronization error check is performed the
check considering a positional deviation. The actual machine position shift considering a servo positional
deviation as well is checked. Depending on the value of a synchronization error, one of two alarms is
issued: an alarm (DS alarm) for deceleration stop, and an alarm (SV alarm) for turning off the servo
system immediately. This check is enabled when a value other than 0 is set in the parameters Nos. 8331
and 8332 for specifying a maximum allowable synchronization error. When using this method of
checking a synchronization error amount, disable "Synchronization error check based on machine
coordinates" in Subsection by setting parameter No. 8314 to 0.

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Synchronization error excessive alarm 1 (DS0002)

When a synchronization error exceeding the value set in parameter No. 8331 is detected, synchronization
error excessive alarm 1 is issued. When synchronization error excessive alarm 1 is issued, the motor
gradually stops. At this time, synchronization error compensation remains enabled, so that the
synchronization error is reduced by compensation. Accordingly, as the synchronization error amount
becomes smaller than the maximum allowable value, the alarm can be reset. If the alarm cannot be reset,
the synchronization error needs to be manually corrected by selecting the correction mode in Subsection.

Synchronization error excessive alarm 2 (SV0002)

When a synchronization error exceeding the value set in parameter No. 8332 is detected, synchronization
error excessive alarm 2 is issued. Before synchronization establishment is performed at power-up time, a
value obtained by multiplying the value set in parameter No. 8332 by the coefficient set in parameter No.
8330 is used for judgment. When synchronization error excessive alarm 2 is issued, the motor
immediately stops as in the case of other servo alarms. Accordingly, the positional difference between the
master axis and slave axis remains uncorrected, so that the alarm cannot be reset usually. In this case, the
synchronization error needs to be manually corrected by selecting the correction mode in Subsection.

1.6.9

Combination with other functions

Explanation

Notes on setting parameters for each axis

Parameters to be set for each axis can be divided into the following four types when they are set for an
axis under axis synchronous control:
(1)  Parameter which must be set the same value to the master and slave axes
(2)  Parameter which needs to be set only to the master axis (data to the slave axis is not used.)
(3)  Parameter which may be set different values to the master and slave axes
(4)  Parameter which needs to be set only to the slave axis (data to the master axis is not used.)
Parameters are listed for each type below. If a parameter is not listed in any table below, assume that the
parameter is of type (1) and set the same value to the master and slave axes.

CAUTION

1 If different values are set in a parameter of type (1) for the master and slave

axes, these axes may not operate as axes under axis synchronous control.

2 When a signal is used to switch between synchronous and normal operation, in

a parameter of type (2), also set a value for each of the master and slave axes.

(1) Parameters which must be set to the same value for the master and slave axes

Parameter

number

Description

12#7

Releasing the assignment of the controlled axis for each axis

1005#0

Whether reference position return has been performed

1005#1

Enabling setting the reference position without dogs

1005#4

Enabling the external deceleration signal for the positive direction in cutting feed for each axis

1005#5

Enabling the external deceleration signal for the negative direction in cutting feed for each axis

1005#6

Turning off MCC signal of the servo amplifier in axis detach

1005#7

Enabling the controlled axis detach signal for each axis

1006#0,#1

Setting a rotary axis

1006#3

Specifying move commands for each axis using diameter programming

1006#5

Direction of manual reference position return

1007#1

Using the same method as for manual reference position return to perform automatic reference
position return (G28)

1007#3

The rotary axis command in an absolute command is the absolute position of the specified value for
the end point coordinates and the sign of the specified value for the direction of rotation.

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