Hitachi SJ7002 Series Instruction Manual page 201

4–40
Using Intelligent Input Terminals
Zero-Return
Functions
69=[ORL]
Opt. Code
and
70=[ORG]
Symbol
Valid for
[1] to [8]
Inputs
Required
P068, P069,
Settings P070, P071
Default Requires
config.
terminal
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A zero-return operation (also called a home-return) occurs when the motor moves the load to a
particular starting position. Using parameter P068, you may select one of three possible types
of zero-return operations. Parameter P069 selects the search direction. The zero pulse input
(also called zone input) signals the arrival at the zero position.
Code Function
P068 Zero-return mode selection
P069 Zero return direction selection
It is generally a requirement (or good practice) to perform a zero-return operation after every
powerup of the inverter. It is possible that the previous power OFF occurred when the load was
not at zero position. Or, it may be that an external force moved the load during the power OFF
period. If you do not perform a zero-return operation after power ON, then the inverter uses the
current position at powerup as the zero position.
Zero-return limit
Zero-return trigger
Encoder Z pulses
The three available zero-return modes differ in the overall search speed, final approach
direction to the origin, and the limit switch input transition (or encoder pulse, if used) causing
the final stop. Choose the zero-return mode that best fits your application.
Low-speed Zero Return:
1. Motor accelerates for the specified
acceleration time to the low zero-
return speed
2. Motor runs at the low zero-return
speed
3. Inverter stops motor and sets position
value to zero when [ORL] signal
turns ON
High-speed 1 Zero Return:
1. Motor accelerates for specified
acceleration time to high zero-return
speed
2. Motor runs at high zero-return speed
3. Motor starts deceleration when
[ORL] signal turns ON
4. Motor runs in reverse direction at
low-speed zero-return speed
5. Inverter stops motor and sets
position value to zero when [ORL]
signal turns OFF
Data
00
01
02
00
01
[ORL]
Inverter
[ORG] Output to motor
[Z]
P070 Low-speed zero-return level
Output
1
frequency
0
[ORG]
[ORL]
P071 High zero-return level
Output
frequency
1
0
[ORG]
[ORL]
Description
Low speed
High speed 1
High speed 2
Forward
Reverse
2
Origin
Position
2
3
Origin
Position
5
4
P070 Low-speed zero-
return level