YASKAWA MP2000 Series User Manual page 160

( 8 ) Zero Point Return Operation and Parameters
With an incremental encoder, there are 17 different methods that can be performed for the zero point return operation.
This section explains the operation that occurs after starting a zero point return and the parameters that need to be set
before executing the command.
[ a ] DEC1 + Phase-C Method (OW3C = 0)

Operation after Zero Point Return Starts
Travel is started at the zero point return speed in the direction specified in the parameters.
When the rising edge of the DEC1 signal is detected, the speed is reduced to the approach speed.
When the first phase-C pulse is detected after passing the DEC1 signal at the approach speed, the speed is reduced to
the creep speed and positioning is performed.
When the positioning has been completed, a machine coordinate system is established with the final position as the
zero point.
 The moving amount after the phase-C pulse is detected is set in the Zero Point Return Travel Distance, (OL42).
 If an OT signal is detected during the zero point return operation, an OT alarm will occur.
N-OT (DI_4)

Parameters to be Set
Parameter
Fixed Parameter
No. 1, Bit 5
Fixed Parameter
No. 21, Bit 0
OW05, Bit 8
OW09, Bit 3
OL10
OW18
OW3C
OL3E
OL40
OL42
Zero Point Return
Travel Distance
(OL 42)
Zero Point
Creep Rate
(OL 40)
Name
Set whether or not to invert the polarity of DI_5 signal used as DEC1 signal.
Deceleration LS
However, the Zero Point Return Deceleration LS Signal (OW05, bit 8)
Inversion Selection
will not be inverted even if this bit is set to 1 (invert).
Deceleration LS Signal
Select the signal to be used as DEC1.
Selection 0: OW05, bit 8, 1: DI_5
Zero Point Return
Used to input DEC1 signal from the ladder program when the bit 0 of fixed
Deceleration LS Signal
parameter No.21 is 0.
(DEC1)
Zero Point Return
Set the zero point return direction.
Direction Selection 0: Reverse rotation (default), 1: Forward rotation
Speed Reference
Set the speed to use when starting a zero point return.
Setting
Only a positive value can be set; a negative value will result in an error.
This parameter allows the Zero Point Return speed to be changed without
changing the Speed Reference Setting (OL10). Set the speed as a per-
centage of the Speed Reference Setting. This setting can be changed during
Override
operation.
Setting range: 0 to 32767 (0% to 327.67%) Setting unit: 1 = 0.01%
Example: Setting for 50%: 5000
Zero Point Return
0: DEC1 + Phase-C
Method
Set the speed to use after detecting the DEC1 signal.
Approach Speed
Only a positive value can be set; a negative value will result in an error.
Set the speed to use after detecting the first phase-C pulse after passing the
Creep Rate
DEC1 signal. Only a positive value can be set; a negative value will result in
an error.
Set the travel distance from the point where the first phase-C pulse is
Zero Point Return Travel
detected after passing the DEC1 signal.
Distance
If the sign is positive, travel will be toward the zero point return direction; if
the sign is negative, travel will be away from the zero point return direction.
Approach Speed
(OL 3E)
Speed Reference Setting
(OL 10)
DEC1 signal (DI_5 or OW
Phase-C pulse
Setting
7.2 Motion Command Details
7.2.3 Zero Point Return (ZRET)
Start
05, bit 8)
P-OT (DI_3)
7
7-21