FANUC Series 0i-MODEL F Plus. CONNECTION MANUAL (FUNCTION) - page 170

8. MULTI-PATH CONTROL

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8.6

SYNCHRONOUS/COMPOSITE CONTROL

Overview

Multi-path control, which has multiple independent control paths built in, is used for such purposes as
controlling multiple turrets of a complex lathe. The axes (such as X1-and Z1-axes) belonging to path 1
are controlled by commands in path 1, and the axes (such as X2- and Z2-axes) belonging to path 2 are
controlled by commands in path 2.

Independent control in each path

Turret 1

Turret 2

Workpiece 2

Workpiece 1

Machining is performed
by a path 1 program.

Machining is performed
by a path 2 program.

Fig. 8.6 (a)

This function enables synchronous control between paths or within a path, composite control between
paths, and superimposed control between paths, as explained below.

Synchronous control

Synchronization of an axis in one path with an axis in another path
(Example)

Synchronization of the Z1-axis (master) with the Z2-axis (slave)

Workpiece

Z2 (synchronized with
the Z1-axis)

Turret 1

Machining is performed by a path 1 program.

Fig. 8.6 (b)

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Synchronization of an axis in one path with another axis in the same path
(Example)

Synchronization of the Z1-axis (master) with the B1-axis (slave)

Workpiece

B1 (synchronized with the Z1-axis)

Turret 1

Tail stock

Fig. 8.6 (c)

Composite control

Interchanging move commands for an axis in one path with those for an axis in another path.
(Example)

Interchanging commands between the X1- and X2-axes

→

Control both X2- and Z1-axes by commands in a path 1 program

Control both X1- and Z2-axes by commands in a path 2 program

Turret 1

Turret 2

Workpiece 2

Workpiece 1

Machining is performed
by a path 1 program.

Machining is performed
by a path 2 program.

Fig. 8.6 (d)

8.6.1

Synchronous Control

An axis in one path can be synchronized with another axis in the same path or an axis in another path.
This is done by issuing the same move commands for one axis (synchronous master axis) to another axis
(synchronous slave axis). Using bit 0 (SMRx) of parameter No. 8162 can cause the slave axis to move in
the direction opposite to that of the master axis. It is possible to place either the master or slave axis in a
parking state, which means to discontinue giving move commands to a servo system. No coordinates are
updated in the parking state. However, the absolute and relative coordinates can be updated using bit 2
(PKUx) of parameter No. 8162.

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Explanation

Setting

Specify which axis is to be the synchronous master axis, with parameter No. 8180, using the path number
and the axis number.
(Example)

For an axis configuration in which all paths consist of X, Z, and Y axes

To synchronize the Z4-axis (slave) with the Z1-axis (master):

Parameter No. 8180z of path 4 = 102

To synchronize the X8-axis (slave) with the X5-axis (master):

Parameter No. 8180x of path 8 = 501

To synchronize the Y1-axis (slave) with the X1-axis (master):

Parameter No. 8180y of path 1 = 101

Programming

Both before and after the M codes for a start and a cancellation of synchronous control, specify a waiting
M code.
Master axis path

Slave axis path

M100P12;

M100P12; .................... Waiting

M200; ........................... Start of synchronous control

M101P12;

M101P12; .................... Waiting

Independent operation Independent operation
:

M100P12;

M100P12; .................... Waiting

M201; ......................... Cancellation of synchronous control

M101P12;

M101P12; .................... Waiting

Signal operation

When synchronization begins or ends (when an M code is issued, for example), the synchronous control
axis selection signals SYNC1 to SYNC8<Gn138> for the slave axis (from the PMC to the CNC) are
changed from "0" to "1" (to begin synchronization) or from "1" to "0" (to terminate synchronization). To
place an axis in a parking state, a parking signal PK1 to PK8<Gn122> is set to "1" for the target axis.

Examples of applications

The following operations can be performed by using the synchronization functions together with the
parking function, which causes move commands for an axis to be ignored and keeps the axis at a rest.
(1) Moving an axis in one path in synchronization with an axis in another path (Both master and slave

axes move.)
Example 1)

Synchronizing the Z2-axis (slave) with the Z1-axis (master) (machining with both ends of a
workpiece chucked)

Z2 (synchronized with the Z1-axis)

Turret 1

Fig. 8.6.1 (a)

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Example 2)

Synchronizing the X2- and Z2-axes (master) with the X1- and Z1-axes (slave) (balance cutting)

Turret 1

Turret 2

Fig. 8.6.1 (b)

Example 3)

Synchronizing the B1-axis (slave) (tail stock axis) with the Z1-axis (master)

Workpiece 1

B1 (synchronized with the Z1-axis)

Turret 1

Tail stock

Fig. 8.6.1 (c)

(2) Placing the movement along the synchronous master axis in the stopped state using a parking signal

is referred to as master parking. In this state, the tool will move along the slave axes only. In contrast,
placing the synchronous slave axes in the stopped state is referred to as slave parking. In this state,
the tool will move along the master axis only. This makes it possible to control a single motor from
both paths 1 and 2.

Example 4)

Sharing one motor with the Z1- and Z2-axes (assuming that the motor is linked to the Z1-axis)

Master axis parking

Turret 1

Turret 2

The X2- and Z1-axes are moved by commands
in a path 2 program (by synchronizing the
Z1-axis (slave) with the Z2-axis (master)). At this
point, the Z2-axis (master) is kept in a parking
state.

Fig. 8.6.1 (d)

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Slave axis parking

Turret 1

Turret 2

The X1- and Z1-axes are moved by commands in
a path 1 program (by synchronizing the Z2-axis
(slave) with the Z1-axis (master)). At this point,
the Z2-axis (slave) is kept in a parking state.

Fig. 8.6.1 (e)

Parking causes the positional relations between machine, absolute, and relative coordinates to shift. After
reference position return, therefore, set the workpiece coordinate system.

Reference position return and its check during synchronous control

If a reference position return command is issued for a synchronous master axis during synchronous
control, it is executed normally for the master axis, but the slave axis does not return to its reference
position (the slave axis only moves in synchronization with the reference position return of the master
axis).
An exception is for automatic reference position return (G28) issued when the master axis is in a parking
state, in which the amount of movement is calculated so that the slave axis returns to its reference position.
In this case, a reference position return has been carried for the slave axis. If the reference position of the
slave axis has not been established, alarm PS0354 “THE G28 WAS INSTRUCTED IN WITH THE REF
POS NOT FIXED IN SYNC MODE” will result.

If, in Cs axis synchronous control, the master axis is not in the parking state and the reference position of
the master axis has not been established, a reference position return operation will be performed in
reference to the master axis machine position, with the G28 command for the master axis.
If the master axis is in the parking state and the reference position of the slave axis has not been
established, a reference position return operation will be performed in reference to the slave axis machine
position, with the G28 command for the master axis.

If more than one slave axis belongs to one master axis, a reference position return command is executed
so that the lowest-numbered slave axis returns to its reference position. If the master axis in one path is
subjected to both synchronization with an axis in the same path and synchronization with an axis in the
other path simultaneously, the lowest-numbered slave axis in the two paths is moved to the reference
position.

A return to the second (third or fourth) reference position by the G30 command works in the same way as
G28. In other words, usually only the master axis moves to the second (third or fourth) reference position.
If the master axis is parking, the lowest-numbered axis is caused to move to its second (third or fourth)
reference position.
If a reference position return check (G27) is specified during synchronous control, the master and slave
axes move to the specified position. Upon completion of movement, a check is made to see whether the
master axis is at its reference position (no check is made for the salve axes) unless the master axis is in a
parking state, in which case a check is made upon completion of positioning to see whether the
lowest-numbered slave axis is at its reference position.

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Out-of-synchronization detection

The term synchronous control used here only refers to an operation in which the same move command is
issued to multiple different servo systems at one time. Note that synchronous control does not involve
out-of-synchronization compensation, in which the positional deviation between multiple servo motors is
constantly checked and one of the servo motors is subjected to compensation to reduce the deviation.
However, using bit 1 (SERx) of parameter No. 8162 can specify detection of out-of-synchronization.
When the out-of-synchronization state is detected, the synchronization mode is canceled immediately
using bit 6 (SESx) of parameter No. 8169, alarm SV0407, “EXCESS ERROR” is issued and the servo
ready signal is turned off, or the excess synchronization error signal SEO <Fn559> is output.

Automatic setting of a workpiece coordinate system

When synchronous control is started in a workpiece coordinate system, it is possible to specify the
workpiece coordinate system automatically. When synchronous control for a workpiece coordinate
system is terminated, it is possible to return the workpiece coordinate system to ordinary machining (not
synchronous control). The explanation of the workpiece coordinate system used during synchronous
control follows. When synchronous control is used to move an axis differently from the way originally
specified, for example, the master axis may be placed in a parking state, while the slave axis is allowed to
move. In such a case, it will be convenient if a coordinate system that indicates the current position of the
slave axis is used as a workpiece coordinate system for the master axis. Conventionally, this workpiece
coordinate system must be specified by program when synchronous control is started, because the
workpiece coordinate system does not originally belong to the master axis. This automatic workpiece
coordinate system setting function for synchronous control sets up this workpiece coordinate system
automatically. This function can also resume the original workpiece coordinate system for the master axis
automatically. Note that the workpiece coordinates of a salve axis can be automatically set through
appropriate parameter setting at the end of synchronous control only.

Setting and commands

In addition to setting ordinary synchronous control, parameters must be specified as follows:
(1) To set up a workpiece coordinate system for synchronous control automatically when starting

synchronous control
Set bit 1 (SPMx) of parameter No. 8163 to 1.

Set parameter No. 8185 with the coordinates of the slave axis reference position relative to the
coordinates of the master axis when the master axis is at the reference position.

(2) To resume the ordinary workpiece coordinate system automatically when terminating synchronous

control
Set bit 2 (SPSx) of parameter No. 8163 to 1. (Only the parameter of the master axis.)
Set parameter No. 1250 with the master axis coordinates in the workpiece coordinate system when
the master axis is at the reference position.

This synchronous control can be specified using the synchronous control axis selection signals
(SYNC1 to SYNC8) similarly to the ordinary synchronous control. When the signals are raised to
start synchronous control, a workpiece coordinate system for the master axis is automatically set up.
When the signals are dropped to terminate synchronous control, the original workpiece coordinate
system for the master axis is resumed automatically.

Workpiece coordinate calculation method

(1) Workpiece coordinate system for synchronous control

(Master axis workpiece coordinate value) = (parameter No. 8185 for the master axis)

(slave axis machine coordinate value) .............. <1>

+ (master axis machine coordinate value) ............ <2>

<1> +: Bit 4 (SCDx) of parameter No. 8163 for the master axis = 0

-: Bit 4 (SCDx) of parameter No. 8163 for the master axis = 1

<2> Bit 3 (SCMx) of parameter No. 8163 for the master axis = 1 only

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(2) Workpiece coordinate system for ordinary operation

(Master axis workpiece coordinate value)
= (parameter No. 1250 for the master axis) +(master axis machine coordinate value)

Caution

CAUTION

The same least command and input increments must apply to both master and
slave axes.

Note

NOTE

1 If more than one slave axis is synchronized with one master axis, the master

axis is set with the workpiece coordinate system that corresponds to the current
position of the first slave axis that is synchronized with the master axis.

2 A coordinate system can also be set with consideration given to tool offset,

through appropriate parameter settings. So, the coordinate system is set up
normally even when tool geometry compensation is applied.

8.6.2

Composite Control

Move commands can be interchanged between an axis in one path and an axis in another path. In other
words, when a machining program is executed for one path, actual machining can be performed with an
axis in the other path. Coordinate systems can also be switched automatically between independent
control and composite control.

Explanation

Setting

Specify which axis is to interchange with which axis, with parameter No. 8183, using the path numbers
and the axis numbers.
Example)

For an axis configuration in which all paths consist of X, Z, and Y axes

Between the Z1- and Z4-axes:

Parameter No. 8183z of path 4 = 102

Between the X5- and X8-axes:

Parameter No. 8183x of path 8 = 501

Between the X1- and Y2-axes:

Parameter No. 8183y of path 2 = 101

To set up coordinate systems automatically when composite control begins or ends, set bits 4 (MPMx)
and 5 (MPSx) of parameter No. 8162 to 1, and specify the positional relationship between the coordinate
systems in parameter No. 8184.

Programming

Both before and after the M codes for a start and a cancellation of composite control, specify a waiting M
code.
Composite control source Composite control destination
:

M100P12;

M100P12; ............................... Waiting

M210;...................................... Start of composite control

M101P12;

M101P12; ............................... Waiting

Independent operation

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M100P12;

M100P12; ............................... Waiting

M211; .................................... Cancellation of composite control

M101P12;

M101P12; ............................... Waiting

Signal operation

When you want to start or cancel composite control (when you specify an M code, for example), change
the composite control axis select signal between MIX1 and MIX8<Gn128> for the axis subject to
composite control that is specified with parameter No. 8183 (the signal being sent from the PMC to the
CNC) from "0" to "1" (to start composite control) and from "1" to "0" (to cancel composite control).

Examples of applications

Suppose that a machine has the X1- and Z1-axes belonging to path 1 and the X2- and Z2-axes belonging
to path 2 and that a workpiece moves along the Z1- and Z2-axes as directed by move commands. The
following examples interchange commands between the X1- and X2-axes.

(1) Independent control

Turret 1

Turret 2

Workpiece 2

Workpiece 1

Machining is performed by a path 1 program.

Machining is performed by a path 2 program.

Fig. 8.6.2 (a)

(2) Composite control

Turret 1

Turret 2

Workpiece 2

Workpiece 1

Machining is performed by a path 1 program.

Machining is performed by a path 2 program.

Fig. 8.6.2 (b)

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