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

4. REFERENCE POSITION ESTABLISHMENT

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Reference position establishment with axis synchronous control axes

With axis synchronous control axes, a reference position is established as follows. When a reference mark
for the master or slave axis is detected, a stop takes place temporarily. Then, a feed operation is
performed again at the reference position return FL feedrate. This sequence is repeated until a reference
mark is detected for both the master and slave axes. Then the absolute position is calculated for both the
master and slave axes, and the reference position establishment signal (ZRF1, ZRF2, ...) are set to 1.
After the reference position has been established by the above operation, a synchronization error is
corrected. (Checking for excessive synchronization error alarm 2 is made even during reference position
establishment.)

Scale end

Reference mark

(1)

(2)

(3)

(a)

(b)

(c)

Master axis

Slave axis

Start point

End Point

(Example of 3 points measurement system)

In the above example, the following sequence is executed.
a.

When the reference mark (1) of the master axis is detected, both master axis and slave axis stop.

Both the axes begin to move again at a reference position return FL feedrate.

When the reference mark (a) of the slave axis is detected, both axes stop again.

Both the axes begin to move again at FL feedrate.

Both axes repeat the operation until all point ((2) -> (b) ->(3)) are detected.

When the slave axis detects the third reference mark (c), both the axes end the reference position
establishment.

NOTE

In case of this function is used with axis synchronous control axes, if the value of
parameters Nos. 1883 and 1884 (Distance 1, 2 from the scale zero point to
reference position) for both the master and slave axes is 0, the reference
position is not established. Also, the reference position establishment signals
(ZRF1, ZRF2, ...) are not set to "1".

PMC control axis

In PMC axis control, if the reference position return command (axis control command code 05H) is issued for
an axis having a distance coded linear scale, reference position return is performed according to the reference
position return sequence for the distance coded linear scale.
Specifically, the following operations take place:

Before reference position
establishment

The reference position is established by detecting two, three or four reference marks.
Movement to the reference position is not performed.

After reference position
establishment

Positioning at the reference position is performed.

Arbitrary angular axis control

There are the following limitations when the angular axis control is used.

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(a) It is necessary to use the linear scale with the distance coded reference mark for both the

perpendicular axis and the angular axis.

(b) When the reference point of the perpendicular axis is established, it is necessary to establish the

reference point of the angular axis previously. When perpendicular axis is commanded first or
perpendicular axis and angular axis are commanded simultaneously, the alarm DS0020,
"REFERENCE RETURN INCOMPLETE", is generated.

perpendicular axis is invalid in the manual reference point return.

Note

(1) In the case of the actual interval of reference marks is different from parameter setting value, the

alarm DS1449, "REFERENCE MARK ARE DIFFERENT FROM PARAMETER", occurs.

(2) This function is disabled if any of the following conditions is satisfied:

Either parameter 1821 (mark-1 interval) or parameter 1882 (mark-2 interval) is set to 0.

Parameters Nos. 1821 and 1882 have identical settings.

The difference between the settings made for parameters Nos. 1821 and 1882 is greater than or
equal to twice either setting.

The absolute-position detection function is enabled (bit 5 (APCx) of parameter No.1815 is 1).

(3) A difference of parameter No.1821 (mark-1 interval) and No.1882 (mark-2 interval) must be more

than 4.
Example)

When the scale, which is that mark1 interval is 20.000mm and mark2 interval is 20.004mm, is
used on IS-B machine:

When the detection unit of 0.001mm is selected, parameter No.1821 and No.1882 must be set
20000 and 20004, and the difference of them is 4.

To use such a scale, please adjust the detection unit by modification of parameter No. 1820
(CMR) and No.2084/2085 (flexible feed gear) to make the difference of No.1821 and 1882
more than 4 as following examples.
(a) Set the detection unit=0.0001mm, and parameter No.1821 is set to 200000, parameter

No.1882 is set to 200040

(b) Set the detection unit=0.0005mm, and parameter No.1821 is set to 40000, parameter

No.1882 is set to 40008

NOTE

When the detection unit is changed, parameters relating to the detection unit
(such as the effective area and positional deviation limit) must also be changed
accordingly.

(4) In this procedure, the axis does not stop until two, three or four reference marks are detected. If this

procedure is started at the position near the scale end, the axis does not stop until over travel alarm
occurs. Please care to start at the position that has enough distance from scale end.

Scale end

Reference marks

Start point (Bad)

Start point (Good)

(5) When the axis used this function, the following function can not be used.

Absolute position detection

(6) If axial movement is made in the direction opposite to that of reference position return, the

movement is reversed to the direction of reference position return after three or four reference marks

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have been detected. Steps 3 to 5 of the basic procedure for establishing a reference position are
carried out to establish the reference position.

(7) Straightness compensation function

When the reference position establishment of moving axis is executed after the establishment of
compensation axis, the compensation axis is moved by straightness compensation amount when the
reference point of moving axis is established.

(8)  The reference position establishment is not performed during synchronous control is activated.
(9)  The reference position establishment is not performed during composite control is activated.
(10)  The reference position establishment is not performed during superimposed control is activated.
(11)  No reference position can be established during flexible synchronization control.

Parameter

1802

DC2x

DC4x

[Input type] Parameter input

[Data type] Bit axis

#1 DC4x

When the reference position is established on the linear scale with reference marks:

An absolute position is established by detecting three reference marks.

An absolute position is established by detecting four reference marks.

#2 DC2x

Reference position establishment operation for a linear scale with reference marks is

performed as follows:
0:

The setting of bit 1 (DC4) of parameter No. 1802 is followed.

An absolute position is established by detecting two reference marks.

NOTE

1 When this parameter is set to 1, specify the direction of the scale

zero point by setting bit 4 (SCP) of parameter No. 1817.

2 When a rotary encoder with absolute address reference marks is

used, this parameter is invalid. Even when this parameter is set to
1, the setting of bit 1 (DC4) of parameter No. 1802 is followed.

1815

DCRx

DCLx

OPTx

RVSx

[Input type] Parameter input

[Data type] Bit axis

NOTE

When at least one of these parameters is set, the power must be
turned off before operation is continued.

RVSx

When the scale without rotary data is used:

The CNC does not maintain the rotary data.

The CNC maintains the rotary data.

This parameter is effective in the axis that satisfies either of the following conditions.
-

The axis is rotary axis B type and the movable range is more than one rotation.

Bit 6 (RVLx) of parameter No.11802 is 1.

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NOTE

1 In the case of a rotary axis B type whose movable range is over

one rotation, a rotary scale with rotary data had better be used.
Otherwise, a machine coordinate value may get out over a rotation,
in the case of moving over 180 degree during turning off.

2 This parameter is available for the axis that is rotary axis B type or

the axis whose bit 6 (RVLx) of parameter No.11802 is 1. This
parameter is available for the axis with an absolute position
detector (absolute Pulsecoder), a distance coded rotary scale
interface (phase A/B) or a rotary scale with distance-coded
reference marks (serial).

3 If this parameter is available, the machine coordinate value just

before CNC turns off is saved. In the case of moving over the
following amounts during turning off or before reference position
return, a machine coordinate value may get out over a rotation
because CNC saves a machine coordinate value just before CNC
turns off and in following turning on get from the value.
In case of the rotary axis B type :

Over 180 degree

In case of the linear axis type :

Over 1/4 of values set to parameter No.11810.

4 If this parameter is changed, the correspondence between the

machine position and the absolute position detector is lost. So,
establish the reference position again. (Bit 4 (APZx) of parameter
No.1815 is set to 0, and an alarm DS0300, “APC ALARM: NEED
REF RETURN” is issued. The cause that sets bit 4 (APZx) of
parameter No.1815 to 0 is indicated in bit 0 of diagnosis data
No.310).

5 Absolute coordinate value is set by machine coordinate value.

However, after CNC turns on, the workpiece offset such as G92
and G52 executed before CNC turns off is not set.

6 This function cannot be used together with the bit 3 (SCRx) of

parameter No. 1817 that convert scale data.

7 In case of the rotary axis B type and the amount of one rotation of

rotary axis is 360, set the parameter No.1869 to 0. Moreover, set
the parameter No.1240 to 0 because the reference position must
be 0 degree.

8 In case of the rotary axis B type and the amount of one rotation of

rotary axis is not 360, set the parameter No.1869 to the amount of
one rotation. Moreover, set the parameter No.1240 to 0 because
the reference position must be 0 degree.

9 In case of the linear axis type, set the amount of the movement per

one motor rotation to the parameter No.11810.

10 This parameter cannot be used together with the stored stroke limit

check immediately after power-on (bit 0 (DOTx) of parameter
No.1311 is 1).

#1 OPTx

The separate position detector is:

Not to be used (semi-closed system)

To be used (full-closed system)

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NOTE

Set 1 when this function is used.

#2 DCLx

As a separate position detector, a linear scale with reference marks or a linear scale with

an absolute address zero point is:
0:

Not used.

Used.

NOTE

Set 1 when this function is used.

#3 DCRx

As a scale with absolute address reference marks:

A rotary encoder with absolute address reference marks is not used.

A rotary encoder with absolute address reference marks is used.

NOTE

When using a rotary encoder with absolute address reference
marks, bit 2 (DCLx) of parameter No. 1815 set also to 1.

1817

SCPx

[Input type] Parameter input

[Data type] Bit axis

NOTE

When this parameter is set, the power must be turned off before
operation is continued.

#4 SCPx

For two-point measurement (when bit 2 (DC2) of parameter No. 1802 is set to 1), the

scale zero point direction is:
0:

On the minus side. (The reference position is located in the plus direction when
viewed from the scale zero point.)

On the plus side. (The reference position is located in the minus direction when
viewed from the scale zero point.)

NOTE

1 This parameter is valid when bit 2 (DC2) of parameter No. 1802 is

set to 1.

2 If this parameter is set to an incorrect value, an incorrect coordinate

system is established. In such a case, reverse the setting then
perform reference position establishment operation again.

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＋

－

Reference position

Machine coordinate system

9.940

9.960

9.980

Mark 1

Mark 2

Mark 1

Mark 2

Mark 1

Mark 2

Mark 1

Mark 2

Mark 1 = mark 2

0.020

Scale zero point

0.040

●

When parameter SCP = 0

●

When parameter SCP = 1

＋

－

Reference position

Machine coordinate system

9.940

9.960

9.980

Mark 1

Mark 2

Mark 1

Mark 2

Mark 1

Mark 2

Mark 1

Mark 2

Mark 1 = Mark 2

0.020

Scale zero point

0.040

1818

RF2x

RFSx

[Input type] Parameter input

[Data type] Bit axis

#0 RFSx

If G28 is specified for an axis for which a reference position is not established (ZRF = 0)

when a linear scale with an absolute address zero point or a linear scale with absolute
address reference marks is used:
0:

A movement is made to the reference position after reference position establishment
operation.

No movement is made after reference position establishment operation, but the
operation is completed.

NOTE

This parameter disables movement based on the G28 command to
a reference position. So, use this parameter only in special cases.

#1 RF2x

If G28 is specified for an axis for which a reference position is already established (ZRF

= 1) when a linear scale with an absolute address zero point or a linear scale with absolute
address reference marks is used:
0:

A movement is made to the reference position.

No movement is made to the intermediate position and reference position, but the
operation is completed.

NOTE

This parameter disables movement based on the G28 command to
a reference position. So, use this parameter only in special cases.

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1819

DATx

[Input type]

Parameter input

[Data type]

Bit axis

#2 DATx

When a linear scale with an absolute address zero point or a linear scale with absolute

address reference marks is used, the automatic setting of parameters Nos. 1883 and 1884
at manual reference position return time is:
0:

Not performed.

Performed.

The automatic setting procedure is as follows:
<1>  Set an appropriate value in parameters Nos. 1815, 1821, and 1882.
<2>  Position the machine at the reference position by manual operation.
<3>  Set this parameter to 1.

Alarm PS5220, “REFERENCE POINT ADJUSTMENT MODE”, occurs.

<4> Perform a manual reference position return operation. Upon completion of manual

reference position return operation, parameters Nos. 1883 and 1884 are set, and this
parameter is automatically set to 0.
Make a reset to release alarm PS5220.

1869

The amount of one rotation of rotary axis B type (each axis)

NOTE

When this parameter is set, the power must be turned off before
operation is continued.

[Input type] Parameter input

[Data type] Real axis

[Unit of data] deg

[Min. unit of data] Depend on the increment system of the applied axis
[Valid data range] 0 or positive 9 digit of minimum unit of data (Refer to the standard parameter setting

table (B))
(When the increment system is IS-B, 0.0 to +999999.999)
Normally, the amount of one rotation of rotary axis is 360, and the machine position 0 is
the reference position.
In this case, this parameter is set to 0.

For instance, when this parameter is set to 523.000, the amount of one rotation become
523.000 (in the case of IS-B), if it is necessary to set it arbitrarily.

NOTE

1 This parameter is available for only the rotary axis B type with an

absolute position detector (absolute Pulsecoder) or a rotary scale
with distance-coded reference marks (serial), as for the bit 3
(SCRx) of parameter No. 1817 is set to 1 or the bit 0 (RVSx) of
parameter No. 1815 is set to 1.

2 In the case that the amount of one rotation of rotary axis is 360, this

parameter is set to 0.If it is necessary to set an amount of one
rotation of rotary axis arbitrarily, this parameter is set to the amount
of one rotation.

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NOTE

3 When this parameter is set, machine position and position on

absolute position detector become uncorresponding. So, establish
the reference position again. (Consequently, the bit 4 (APZx) of
parameter No. 1815 (indicating that the correspondence is
established) is set to 0, and an alarm DS0300, “APC ALARM:
NEED REF RETURN”, occurs. Why the bit 4 (APZx) of parameter
No. 1815 is set to 0 can be checked using bit 0 of diagnosis data
No.310).

4 This parameter No. 1869 is common in movable range that is

under one rotation (the bit 3 (SCRx) of parameter No. 1817 is set to
1) and movable range that is over one rotation (the bit 0 (RVSx) of
parameter No. 1815 is set to 1).

5 Please set 0 to this parameter if the distance coded rotary scale

interface (phase A/B) is used.

1821

Reference counter size for each axis

NOTE

When this parameter is set, the power must be turned off before
operation is continued.

[Input type] Parameter input

[Data type] 2-word axis

[Unit of data] Detection unit

[Valid data range] 0 to 999999999

Set the interval of reference mark 1 of distance coded linear scale.

1882

Interval of reference mark 2

NOTE

When this parameter is set, the power must be turned off before
operation is continued.

[Input type] Parameter input

[Data type] 2-word axis

[Unit of data] Detection unit

[Valid data range] 0 to 999999999

Set the interval of reference mark 2 of distance coded linear scale.

1883

Distance 1 from the scale zero point to reference position

NOTE

When this parameter is set, the power must be turned off before
operation is continued.

[Input type] Parameter input

[Data type] 2-word axis

[Unit of data] Detection unit

[Valid data range] -999999999 to 999999999

FANUC Series 0i-MODEL F Plus. CONNECTION MANUAL (FUNCTION) - page 101