4 Feed Axis Operation
4.7.1 Homing Method (Absolute Encoder as an Absolute Encoder)
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4.7
Homing
Homing is the act of positioning to move an axis to the machine coordinate origin.
Generally, homing is performed for all feed axes simultaneously, but in some cases homing may be performed
one axis at a time to avoid interference with other axes or the workpiece. Choose whether to perform homing
for all axes simultaneously or for individual axes depending on the load configuration requirements.
There are two types of homing depending on the servomotor encoder used, as described below.
Absolute Encoder Used as an Absolute Encoder (Factory Setting)
In this case, homing refers to positioning to move to the origin. Homing is performed from the host controller
for all axes or individual axes one at a time with the origin as the target position.
In the SERVOPACK, we recommend that you perform absolute position detection as described in
4.5 Abso-
lute Position Detection
if the servomotor has an absolute encoder that is used as an absolute encoder (i.e., the
factory setting).
Absolute position detection enables the recognition of the absolute position in machine coordinates. This elim-
inates the need to perform homing immediately after the power supply is turned ON.
Absolute Encoder Used as an Incremental Encoder (Parameter Pn002.1 = 1)
For incremental encoders, the homing method that is described in
4.7.2 Homing Method When Using an
Absolute Encoder as an Incremental Encoder
is used to return to the origin.
Create an operation sequence so that the homing sequence is executed according to the load configuration
from the host controller. The homing sequence must always be performed immediately after the power supply
is turned ON.
4.7.1
Homing Method (Absolute Encoder as an Absolute Encoder)
If the servomotor’s absolute encoder is used as an absolute encoder (i.e., if parameter Pn002.1 is set to 0), the
current position data is saved after the origin has been set, even if the power supply to the SERVOPACK is
turned OFF and ON again. Therefore, no homing is necessary. However, homing is required when setting up
the machine or attaching a jig to the machine.
In this case, homing performs positioning to the mechanical origin. Perform this positioning to the mechanical
origin as follows:
4.7.2
Homing Method When Using an Absolute Encoder as an Incremental
Encoder
If the servomotor’s absolute encoder is used as an incremental encoder (i.e., if parameter Pn002.1 is set to 1),
the coordinate system and current position data are lost if the power supply to the SERVOPACK is turned OFF
and ON again. Therefore, homing must be performed when the power supply is turned ON again to establish a
new coordinate system.
Select from the following homing methods as appropriate for your particular load configuration.
• Deceleration dog + Phase-C pulse
• Deceleration dog + Zero signal (a signal from EXT1 to EXT3)
• Phase-C pulse
• Zero signal (EXT1 to EXT3)
• OT & phase-C pulse
Homing speed
Mechanical origin