FANUC Series 30i/300i/300is-MODEL A. Machining Center System. User's manual - page 55

15.COMPENSATION FUNCTION

PROGRAMMING

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NOTE

1 In the normal direction control mode, the following

commands cannot be issued. An attempt to issue
any of them results in alarm PS1471 being raised.
- Plane selection command (G17, G18, G19)
- Automatic reference position return(G28)
- 2nd/3rd/4th reference position return(G30)
- Move from the reference position (G29)

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15.5

WORKPIECE SETTING ERROR COMPENSATION

When a workpiece is placed on the machine, the workpiece is not
always placed at an ideal position.
With this function, a displaced workpiece can be machined according
to the program.
This function can compensate for a workpiece setting error on a
rotation axis used with a function involving rotation axis operation
such as a function for tool center point control, function for
3-dimensional cutter compensation, and a tilted working plane
command. So, a workpiece can be machined according to the
program even during tool center point control, 3-dimensional cutter
compensation, and tilted working plane command.

Workpiece setting error

Rotary tool

The coordinates system and the tool automatically
rotate in accordance with the Workpiece setting error.

Workpiece

Fig. 15.5 (a) Outline of workpiece setting error

Format

G54.4 Pn ;

Start workpiece setting error compensation

:
:
G54.4 P0 ;

Cancel workpiece setting error compensation

Pn : Workpiece setting error specification code
n : 1 to 7

A start block and cancellation block for workpiece setting error
compensation suppress buffering.

Workpiece setting error compensation mode

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Explanation
- Workpiece setting error

A workpiece setting error is defined by the following eight variables:

•

X direction error

∆

•

Y direction error

∆

•

Z direction error

∆

•

Rotation direction error

∆

a (rotation error on the X-axis in

degrees)

•

Rotation direction error

∆

b (rotation error on the Y-axis in

degrees)

•

Rotation direction error

∆

c (rotation error on the Z-axis in

degrees)

•

Table rotation axis position 1

•

Table rotation axis position 2

[About

∆

y, and

∆

y, and

∆

z represent the coordinate values of the origin of the

workpiece coordinate system (X'Y'Z' in the figure below, which is
hereinafter referred to as the "workpiece setting coordinate system")
based on a displaced workpiece, as viewed from the original
workpiece coordinate system (XYZ in the figure below).

Coordinate system X'Y'Z'
(workpiece setting coordinate
system) based on the
displaced workpiece

Workpiece coordinate
system XYZ

∆

Workpiece

Correct workpiece position

Displace workpiece

∆

c degrees

Fig. 15.5 (b) Errors in X, Y, and Z directions

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[About

∆

b, and

∆

b, and

∆

c are defined as described below.

The workpiece coordinate system obtained by rotating a workpiece
coordinate system about the X-axis by angle

∆

a, about the Y-axis by

angle

∆

b, and about the Z-axis by angle

∆

c then shifting that

workpiece coordinate system by (

∆

z) from the origin of that

workpiece coordinate system is supposed to match the "workpiece
setting coordinate system".
(Note: In determination of positive/negative rotation, clockwise
rotation is defined to be positive rotation.)

X (= X')

Z’

Y’

∆

Z’

Y’

∆

Z’

Y’

∆

Z’

Y’

(

∆

z )

The workpiece coordinate
system (X,Y,Z) is rotated
about the X-axis by

∆

Further rotated about the
Y-axis by

∆

Further rotated about the
Z-axis by

∆

Workpiece setting
coordinate system

Fig. 15.5 (c) Errors in rotation directions

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The example of Fig. 15.5 (b) assumes that

∆

a =

∆

b = 0 and

∆

represents a nonzero value.

[About table rotation axis position 1 and table rotation axis position 2]

The table rotation axis position means the machine coordinate on the
table rotation axis of a 5-axis machine with a table rotation axis
(machine of table rotation type or composite type) when a workpiece
setting error (displacement from the correct workpiece position to the
actual workpiece position) is measured.
When two table rotation axes are used, set table rotation axis position
1 for the master rotation axis, and set table rotation axis position 2 for
the slave rotation axis.

(As for master rotation axis and slave rotation

axis, refer to the Table 1 described later.)
When only one table rotation axis is used, set table rotation axis
position 1 for the axis.
When no table rotation axis is used, or the machine used is not a
5-axis machine, table rotation axis position 1 and table rotation axis
position 2 need not be set.
No setting can be made for a hypothetical axis.

In the descriptions above, X, Y, and Z represent the three basic axes,
X, Y, and Z, specified by parameter No. 1022.
If the specification of any of the three basic axes, X, Y, and Z, is
missing, alarm PS0436 is issued.

- Setting of a workpiece setting error on the workpiece setting error setting screen

A workpiece setting error is set on the workpiece setting error setting
screen.
For explanations about the setting method, see Chapter 12, "SETTING
AND DISPLAYING DATA," of Part III.

- Workpiece setting error of No. 00 (COMMON)

Each of the values set in No. 00 (COMMON) is added to the
corresponding value of each of No. 01 through No. 07.
Note that rotation direction errors for No.00(COMMON) are not
available.
Example:

Suppose that workpiece setting errors are set as follows:

No. 00 (COMMON)

No. 01

No. 02

X 10.000

x 0.500

x 0.800

Y 0.000

y 0.000

Z 0.000

z 0.000

a 1.500

a 1.800

b 0.000

c 0.000

When the workpiece setting error of No. 01 is selected,
workpiece setting error compensation is performed based on the
following:

∆

x = 10.000+0.500 = 10.500

∆

a = 1.500

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When the workpiece setting error of No. 02 is selected,
workpiece setting error compensation is performed based on the
following:

∆

x = 10.000+0.800 = 10.800

∆

a = 1.800

If the setting of table rotation axis position 1/table rotation axis
position 2 differs between the workpiece setting error of No. 00 and
each workpiece setting error when a 5-axis machine (machine of table
rotation type or composite type) with table rotation axes is used, no
simple additions are made. Instead, before additions are made,
conversion is made to values based on the machine coordinate on a
table rotation axis being 0.
Example:

Suppose that workpiece setting errors are set as follows on a
5-axis machine with table rotation axis C about the Z-axis.

No. 00 (COMMON)

No. 01

X 0.000

x 5.000

y 10.000

y 0.000

z 0.000

0.000

2.000

C -90.000

C 90.000

First, the error values of No. 00 are converted to those based on C
= 0.000.

Next, the error values of No. 01 are converted to those based on C
= 0.000.

∆

y = 5.000,

∆

c = 2.000

C = 0

C positive direction

∆

x = 5.000,

∆

c = 2.000

C = 90

∆

c positive direction

C positive direction

∆

y = 10.000

C = -90

C = 0

∆

x = 10.000

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When the workpiece setting error of No. 01 is selected, workpiece
setting error compensation is performed as follows based on the
converted error values based on C = 0.000:

∆

x = 10.000+0.000 = 10.000

∆

y = 0.000+5.000 = 5.000

∆

c = 2.000

- Least input increment of data and valid data range

[About errors

∆

y, and

∆

The unit of data is the unit of input, and follows the least input
increment for the reference axis specified by parameter No. 1031.

- For metric input

Unit system of reference axis

IS-A

IS-B

IS-C

IS-D

IS-E

Least input increment (mm)

0.01 0.001 0.0001 0.00001 0.000001

Maximum settable value (mm)

999,999.99

999,999.999

99,999.9999

9,999.99999

999.999999

- For inch input

Unit system of reference axis

IS-A

IS-B

IS-C

IS-D

IS-E

Least input increment (inch) 0.001

0.0001

0.00001 0.000001 0.0000001

Maximum settable value (inch)

99,999.999

99,999.9999

9,999.99999

999.999999

99.9999999

[About errors

∆

b, and

∆

With parameter No. 11201, the number of decimal places of the least
input increment can be specified.

Parameter No. 11201

1 2 3 4

Least input increment (deg) 0.1

0.01

0.001

0.0001

Maximum settable value (deg)

99,999,999.9

9999,999.99

999,999.999

99,999.9999

Parameter No. 11201

5 6 7 8

Least input increment (deg) 0.00001

0.000001 0.0000001 0.00000001

Maximum settable value (deg)

9,999.99999

999.999999

99.9999999

9.99999999

Note, however, that a value from 1 to 8 can be specified in parameter
No. 11201.
If a value not within the specifiable range is specified in parameter No.
11201, the least input increment of the reference axis is followed.

Unit system of reference axis

IS-A

IS-B

IS-C

IS-D

IS-E

Least input increment (deg) 0.01

0.001

0.0001 0.00001 0.000001

Maximum settable value (deg)

999,999.99

999,999.999

99,999.9999

9,999.99999

999.999999

x = 10.000,

y = 5.000,

c = 2.000

C = 0

∆

c positive direction

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[About table rotation axis position 1 and table rotation axis position 2]
The unit of data follows the least input increment of each
corresponding rotation axis.

Unit system of rotation axis

IS-A

IS-B

IS-C

IS-D

IS-E

Least input increment (deg) 0.01

0.001

0.0001 0.00001 0.000001

Maximum settable value (deg)

999,999.99

999,999.999

99,999.9999

9,999.99999

999.999999

- "Active workpiece setting error"

In the workpiece setting error compensation mode, "Active workpiece
setting error" on the workpiece setting error setting screen displays the
currently selected workpiece setting error number and workpiece
setting error (sum of the data of the currently selected workpiece
setting error number and the data of No. 00).

If the workpiece setting error compensation mode is not set, "MODE
OFF" is indicated, and 0 is displayed in each data field.

If a 5-axis machine (machine of table rotation type or composite type)
with table rotation axes is used, and a nonzero value is set for table
rotation axis position 1/table rotation axis position 2, error values
obtained by conversion based on the machine coordinates on the table
rotation axes being 0 are displayed.

- Setting of workpiece setting errors with custom macro variables

By using custom macro variables #26000 to #26077, workpiece
setting errors can be read and written.
(The custom macro option is required.)

The numbers of macro variables correspond to Errors as follows :

Error

No.00

(COMMON)

Error

No.01

Error

No.02

Error

No.03

Error

No.04

Error

No.05

Error

No.06

Error

No.07

X direction error

∆

x #26000

#26010

#26020

#26030

#26040

#26050

#26060

#26070

Y direction error

∆

y #26001

#26011

#26021

#26031

#26041

#26051

#26061

#26071

Z direction error

∆

z #26002

#26012

#26022

#26032

#26042

#26052

#26062

#26072

Rotation direction error

∆

a -

#26013

#26023

#26033

#26043

#26053

#26063

#26073

Rotation direction error

∆

b -

#26014

#26024

#26034

#26044

#26054

#26064

#26074

Rotation direction error

∆

c -

#26015

#26025

#26035

#26045

#26055

#26065

#26075

Table rotation axis position 1

#26006

#26016

#26026

#26036

#26046

#26056 #26066

#26076

Table rotation axis position 2

#26007

#26017

#26027

#26037

#26047

#26057 #26067

#26077

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