NSK EDD Megatorque Motor, User Manual, Page: 231 / 398

8. More Advanced Function
— 8-47 —
4) The output BUSY (In-operation) is closed during execution of Home Return. The home position
is in the state of undefined and the System forcibly opens the output HCMP (Home position
defined).
5) When the HLS input changes from OFF to ON, the Motor decelerates and stops. Then it
reverses to get out temporally the area of the home position limit.
6) The Motor reverses its motion again with the velocity set by the parameter HZ (Home Return
near-zero velocity) and rotates until the input HLS changes from OFF to ON again.
7) After detecting the input HLS, the Motor rotates to the nearest phase Z signal. The Motor rotates
further to the position set by the parameter HO (home position offset) and defines the home
position. At this time, the output HCMP closes.
8) When the Motor settles at the home position, the outputs IPOS (In-position) and HOME (Home
Return complete) close to complete the operation.

If the Home Return operation is interrupted, the System cannot define the home position. Entering of the
command for an absolute positioning at this state will cause the warning A5 (Origin undefined).

You can program the command HS in a program channel. This will make you possible to start the Home
Return operation with the inputs RUN (Start program) and PRG (Internal program channel selection).

The pattern of Home Return operation depends on its starting point as illustrated below.
Fig 8-27: Operation pattern of Home Return (In case of OS4, DI0 andHD1)
The output OTMA does not
open during this motion.
: : Starting position of Home Return
: Home Return complete position
Input OTP *ON
(Over travel are in CW
direction) Input OTM: *ON
(Over travel area in CCW
direction) Input HLS ON area
(Near-zero arrea)
CW direction* CCW direction*

Velocity for CCW*

Velocity for CW*
Output OTPA opens
during this motion.
Phase Z
The output OTMA opens
during this motion.
HO

When the Motor reverses its motion by the parameter HD, the CW and CCW (CW
←→
CCW), and OTP and OTM (OTP
←→
OTM) respectively switch positions with each other .