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

4. REFERENCE POSITION ESTABLISHMENT

B-64693EN-1/01

- 754 -

This is the end of reference position adjustment.

(4) The machine will stop at the reference position from now on whenever a reference position return is

made.

NOTE

1 When reference position return with mechanical stopper by grid method is

performed while reference position is established, reference position return with
mechanical stopper by grid method is performed again.

2 When the relation of the sign of parameters Nos.1844 and 1850 is contradicted,

the amount of the grid shift becomes effective only below the capacity of the
Reference counter.

Parameter

1006

ZMIx

[Input type] Parameter input

[Data type] Bit axis

NOTE

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

#5 ZMIx

The direction of manual reference position return is:

+ direction

- direction

1008

SFDx

[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 SFDx

In reference position return based on the grid method, the reference position shift function

is:
0:

Disabled

Enabled

1425

FL rate of the reference position return for each axis

[Input type] Parameter input

[Data type] Real axis

[Unit of data] mm/min, inch/min, deg/min (machine unit)

[Min. unit of data] Depend on the increment system of the applied axis
[Valid data range] Refer to the standard parameter setting table (C)

(When the increment system is IS-B, 0.0 to +999000.0)
Set feedrate (FL rate) after deceleration when the reference position return is performed
for each axis.

B-64693EN-1/01

4. REFERENCE POSITION ESTABLISHMENT

- 755 -

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 a reference counter size.
As a reference counter size, specify a grid interval for reference position return based on
the grid method.
When a value less than 0 is set, the specification of 10000 is assumed.
When a linear scale with absolute address reference marks is used, set the interval of
mark 1.

1844

Distance to the first grid point when the reference position shift amount in the reference position shift

function is 0 or when a reference position return is made by grid shift

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

(1) When the reference position shift function is enabled (when bit 4 (SFDx) of

parameter No. 1008 is set to 1)

Set the distance (detection unit) to the first grid point from a point at which the
deceleration dog is released when the reference position shift (parameter No. 1850)
is set to 0.

(2) When a reference position return is made by grid shift with a setting not to use

reference position setting without dogs (when bit 4 (SFDx) of parameter No. 1008 is
set to 0, and bit 1 (DLZx) of parameter No. 1005 is set to 0)

Set the distance to the first grid point from a point at which the deceleration dog is
released. (Detection unit)

(3) When a reference position return is made by grid shift with a setting to use reference

position setting without dogs (when bit 4 (SFDx) of parameter No. 1008 is set to 0,
and bit 1 (DLZx) of parameter No. 1005 is set to 1)

Set the distance from the start position for reference position setting without dogs to
the first grid point. (Detection unit)

NOTE

1 When the reference position shift function is enabled (when bit 4

(SFDx) of parameter No. 1008 is set to 1)
When bit 4 (SFDx) of parameter No. 1008 is set to 1, the distance
from a point at which the deceleration dog is released to the first
grid point (parameter No. 1844) is set to 0, and reference position
shift (parameter No. 1850) is set to 0, a manual reference position
return allows this parameter to be set automatically. Do not change
an automatically set value.

4. REFERENCE POSITION ESTABLISHMENT

B-64693EN-1/01

- 756 -

NOTE

2 When a reference position return is made by grid shift with a setting

not to use reference position setting without dogs (when bit 4
(SFDx) of parameter No. 1008 is set to 0, and bit 1 (DLZx) of
parameter No. 1005 is set to 0)
When a manual reference position return using deceleration dogs
is made, this parameter is set automatically.

3 When a reference position return is made by grid shift with a setting

to use reference position setting without dogs (when bit 4 (SFDx) of
parameter No. 1008 is set to 0, and bit 1 (DLZx) of parameter No.
1005 is set to 1)
When a reference position setting without dogs is made, this
parameter is set automatically.

1850

Grid shift and reference position shift 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] -99999999 to 99999999

To shift the reference position, the grid can be shifted by the amount set in this parameter.
Grid shift amount that can be set is a value less than reference counter size.
When bit 4 (SFDx) of parameter No.1008 is 0, it is grid shift, and when bit 4 (SFDx) of
parameter No.1008 is 1, it is reference point shift.

NOTE

For setting the reference position without dogs, only the grid shift
function can be used. (The reference position shift function cannot
be used.)

7184

Second butting feedrate in reference point setting with mechanical stopper or butting feedrate in

reference point setting with mechanical stopper by Grid Method

[Input type] Parameter input

[Data type] Real axis

[Unit of data] mm/min, inch/min, deg/min (machine unit)

[Min. unit of data] Depend on the increment system of the applied axis
[Valid data range] Refer to the standard parameter setting table (C)

(When the increment system is IS-B, 0.0 to +999000.0)
This parameter sets a feedrate used to butt against the stopper along an axis.

7186

Torque limit value in reference point setting with mechanical stopper

[Input type] Parameter input

[Data type] Byte axis

[Valid data range] 0 to 100

B-64693EN-1/01

4. REFERENCE POSITION ESTABLISHMENT

- 757 -

This parameter sets a torque limit value. A value from 0 to 100 corresponds to 0% to 39%.
The torque limit value is obtained by multiplying the setting by 1/255. If more than 39%
is to be set, use parameter No. 7187.

NOTE

When 0 is set in this parameter, 100% is assumed.

7187

Torque limit value in reference point setting with mechanical stopper or reference point setting with

mechanical stopper by Grid Method

[Input type] Parameter input

[Data type] Word axis

[Valid data range] 0 to 255

This parameter sets a torque limit value. As for the setting value, 0-255 corresponds to
0% to 100%.
When this parameter is set for reference point setting with mechanical stopper, parameter
No.7186 is ignored. When this parameter is set to 0, the setting of parameter No.7186 is
used.
However, in case of reference point setting with mechanical stopper by Grid Method,
only this parameter is valid. If this parameter is set to 0, 100% of the rated torque is
assumed even if parameter No.7186 is set up.

7188

RNWx

GRSx

[Input type] Parameter input

[Data type] Bit axis

#0 GRSx

Reference point setting with mechanical stopper by Grid Method is:

Not performed.

Performed.

#7 RNWx

During reference point setting with mechanical stopper by Grid Method, until the sign of

servo position deviation is inverted, the grid is

Not ignored.

Ignored.

Warning

WARNING

When cycle operation of Reference point setting with mechanical stopper by grid
method is completed, Reference position return end signals ZPx <Fn094> turns
to "1".
Before completing the cycle operation, namely, when the RESET is executed or
operation mode is changed to a mode other than REF mode in the state of ZPx
signal is "0", the cycle operation is broken off. In such a case, e

mergency stop is

applied.

And, start over Reference point setting with mechanical stopper by grid

method after emergency stop cancellation.

4. REFERENCE POSITION ESTABLISHMENT

B-64693EN-1/01

- 758 -

4.8

DISTANCE CODED LINEAR SCALE INTERFACE

Overview

The interval of each reference marks (one-rotation signal) of distance coded linear scale are variable.
Accordingly, if the interval is determined, the absolute position can be determined. The CNC measures
the interval of reference marks by axis moving of short distance and determines the absolute position.
Consequently the reference position can be established without moving to reference position.

10.02

10.04

20.02

20.00

Reference mark 1

Reference mark 2 Reference mark 1 Reference mark 2 Reference mark 1

Fig. 4.8 (a) Example of distance coded linear scale

Procedure for reference position establishment

- Procedure

(1) Select the JOG mode, and set the manual reference position return selection signal ZRN to 1.
(2) Set the feed axis and direction selection signal(+J1, -J1, +J2, -J2, …) to "1" and feed the axis for

which you want to establish a reference point.

(3) The axis is fed at a constant low speed (reference position return FL feedrate specified by parameter

No. 1425 setting).

(4) When a reference mark is detected, the axis stops, then the axis is fed at a constant low speed again.
(5) Above (4) is executed repeatedly until two, three or four reference marks are detected. And absolute

position is determined and the reference position establishment signal (ZRF1, ZRF2, ZRF3, …)
turns to 1.

(A number of reference marks is determined by the bits 2 (DC2) and 1 (DC4x) of parameter No.
1802.)

CAUTION

When the scale correctly detects the mark, the reference position is correctly
established regardless of the number of detected reference marks. When the
scale misreads the mark position, the alarm DS1449 "REFERENCE MARK ARE
DIFFERENT FROM PARAMETER" is usually issued. However, if the interval of
the detected mark is same as the parameters, the alarm might not be issued and
the reference position might be established with the wrong position.

It is reliable to avoid misreading the reference marks by using more number of
detecting reference marks. It is recommended that the reference position is
established by detecting four reference marks though the number of detecting
reference marks can be selected from two to four reference marks number.

B-64693EN-1/01

4. REFERENCE POSITION ESTABLISHMENT

- 759 -

The timing chart for this procedure is given below.

JOG

ZRN

+J1

Reference mark

ZRF1

Feedrate

FL rate

Fig. 4.8 (b) Timing chart for reference position establishment

Procedure for establishing a reference position through automatic operation

If an automatic reference position returns (G28) is specified before a reference position is not established,
steps (3) to (5) above are performed automatically.
After the reference position is established, the automatic reference position return is performed.

Stopping the operation for establishing a reference position

The operation for establishing a reference position is stopped if any of
the following operations is performed in steps (3) to (5), described above.
-

Reset

Setting the feed axis and direction selection signal (+J1, -J1, +J2, -J2, etc.) to 0

If any of the following operations is performed during the operation of automatic reference position
return (G28) before a reference position is not established, the operation for establishing a reference
position stops:
-

Reset

Performing feed hold during movement from an intermediate position

If the operation for establishing a reference position is stopped by an operation other than a reset, the
operation for establishing a reference position must be reset and resumed.

Explanation

Reference Position Return

(1) When axis is moved in REF mode while reference position is not established, reference position

establishment procedure is executed.

(2) When axis is moved in REF mode while reference position is established, reference position

establishment procedure is not executed and axis is moved to reference position.

(3) When the reference position is not established and the reference position return command (G28) is

executed, the reference position establishment procedure is executed. The next movement the axis
depends on the setting of bit 0 (RFS) of parameter No. 1818.

(4) When the reference position is already established and the reference position command (G28) is

executed, the movement of the axis depends on the setting of bit 1 (RF2) of parameter No. 1818.

Distance coded rotary encoder

In case of setting a rotary axis, if bit 3 (DCRx) of parameter No. 1815 is set, the setting axis is regarded as
being equipped with a distance coded rotary encoder.
In case of distance coded rotary encoder, the marker interval may be different from parameter setting
value at the joint of the encircled circle (a-b section of the following figure). When the reference point
return is executed through this section, it is not able to establish the reference point. Therefore, in case of

4. REFERENCE POSITION ESTABLISHMENT

B-64693EN-1/01

- 760 -

distance coded rotary encoder, if the reference point return is started for B point from A point of below
figure, the reference point is not established yet at B point. The reference point return is re-started for C
point. The reference point return procedure is finished at C point.

9.64

9.98

9.96

19.66

20.02

9.94

20.00

In case of distance coded rotary encoder, only the measurement by three points or four points is
possible. (Bit 2 (DC2) of parameter No. 1802 is disregarded as 0.)

- Rotary axis (B type)

The distance coded rotary encoder does not have the rotary data. For example, 30.000 degree and 390.000
degree have completely same scale data though their position is different from each other by just one
rotation. When distance coded rotary encoder is used and rotary axis is B type (bit 0 of parameter
No.1006 is 1 and bit 1 of parameter No.1006 is 1 (machine coordinate system of rotary axis is linear axis
type)), reference position established by this function is rounded by the amount of movement per a
rotation of rotary axis even if the axis is rotated more than one rotation.
For this case, when the Reference point is established, correct machine coordinates can be established
even the turn of the machine more than one revolution by setting the bit 0 (RVSx) of parameter No.1815
to "1".
Moreover, the present machine coordinates are stored immediately before the power is turned off when
the parameter RSVx is set to 1. Therefore, immediately after the power is turned on again, this function
can restore the approximate machine coordinates and enables the function for checking the stored stroke
during the time from power-on to the reference position establishment. Even before the reference position
is established by reference position return, the stored stroke check can be performed using approximate
machine coordinates. Absolute coordinates are set based on the machine coordinates. Data such as
workpiece offsets specified by G92, G52, and so on before the power is turned off, however, is not set. If
bit 3 (PPD) of parameter No. 3104 is set to 1, the relative position indication is preset.

Axis synchronous control

In case of the synchronization establishment of the axis synchronous control, when the position is set
immediately after turning on of the power, the synchronization establishment is executed.

Parameter setting procedure
1

The bit 0 (RVSx) of parameter No.1815 is set to 0, the power supply of CNC is turned off once, and
it turns on again.

The reference position is established by manual reference position return.

The reference position returns, and it moves to the reference position.

The bit 0 (RVSx) of parameter No.1815 is set to 1, the power supply of CNC is turned off once, and
it turns on again.

B-64693EN-1/01

4. REFERENCE POSITION ESTABLISHMENT

- 761 -

NOTE

1 a machine coordinate value may get out over a rotation, in the case of moving

over 180 degree during turning off, because CNC saves a machine coordinate
value just before CNC turns off and in following turning on get from the value.

2 Temporary absolute coordinate setting and this function cannot be used together

within same axis.

3 This function can be used only when the amount of one rotation of rotary axis is

360 degree. Set 0 to the parameter No.1869.
If the values other than 0 are set, an alarm DS1448, "ILLEGAL PARAMETER
(D.C.S.)", is issued.

4 Set the parameter No.1240 to 0 because the reference position must be 0

degree.

5 If the tool is already beyond a stored stroke immediately after the power is

turned on, an overtravel alarm (OT alarm) is issued.
In this case, release the alarm by moving the tool along the axis in the direction
that does not cause overtravel.
If bit 6 (LZR) of parameter No. 1300 is set to 1, the function for checking the
stored stroke during the time from power–on to the reference position
establishment is disabled.

6 When the power is turned on while the

key and the <P> address key are

held down, the stored stroke check immediately after power-on is disabled.
(When the MDI keys are provided as standard keys)
(When performing this operation, exercise special care.)
In this case, machine coordinates and absolute coordinates are set.
When the compact type MDI keys are used, the stored stroke immediately after
power-on is disabled by holding down the

key and <O> address key at

power-on.

Requirements when this function is used with axis synchronous control axes

When this function is used with axis synchronous control axes, the distance coded linear scale used for
the master axis and that used for the slave axis must have reference marks placed at identical intervals.
(Set identical values in parameters Nos. 1821 and 1882 for both the master and slave axes.)
A distance coded linear scale can be installed on the master and slave axes either in the same or opposite
direction.
This function does not work unless the use of this function is specified for both the master and slave axes
(bit 2 (DCL) of parameter No. 1815 is 1).
Also, in all parameters related to this function, except parameters Nos. 1883 and 1884 (distance from the
scale zero point to reference position 1, 2), set identical values for both the master and slave axes.
If a parameter value for the master axis differs from the corresponding parameter value for the slave axis,
alarm SV1051 "ILLEGAL SYNCHRONOUS AXIS" is issued.

NOTE

1 When this function is used with axis synchronous control axes for which the

operation mode is switched between synchronization operation and normal
operation, this function is enabled only if the synchronization select signal
(SYNC1, SYNC2, ...) is 1. (During establishment of a reference position, the
synchronization select signal status must be maintained.)

2 When this function is used by the axis synchronous control, only one axis is

available for the slave axis. When the slave axis of the axis synchronous control
is two or more settings, the alarm DS0027 "MISMATCH OF SYNCHRONOUS
AXIS(D.C.S)" is issued.

FANUC Series 0i-MODEL F Plus. CONNECTION MANUAL (FUNCTION) - page 100