Fuji Electric ALPHA7, User Manual

Page: 199 / 662

CHAPTER 4 PARAMETER
4-8
Basic Parameters
4
PA1_02 INC/ABS system selection
No. Name Setting range
Default
value
Change
02
INC/ABS selection 0: Incremental system 1:Absolute system
2: Non-overflow absolute system
0 Power
Select either the relative position (incremental) system or absolute position system.
Reference
value
Function Description
0
Relative position
(incremental) system The current position is lost after the control power is turned
off. Homing must be performed again.
1
Absolute position
system
The current position is stored in memory even after the
control power is turned off. Homing is unnecessary. You
can operate in the limited range. If the operation range is
exceeded, an alarm and stoppage are caused.
(Operation range: between -32767 and +32766 revolutions
of motor shaft)
2
Non-overflow absolute
system (not detect the
multi-turn overflow)
The current position is stored in memory even after the
control power is turned off. Homing is unnecessary.
Because there is no limit in the operation range, this
system is best for the control of the rotating body. (The
multi-turn data over flow alarm is not detected.)
Multi-rotation data should be processed at the host
controller suitably.
Refer to
■ Precautions when setting endless ABS for
precaution relating to this setting value.
To establish an absolute position system, set this parameter at "1" or "2." In addition, install the
optional absolute backup battery.
Because a multi-rotation data loss alarm (dL1 alarm) is detected when the power is turned on,
perform position presetting to remove the alarm and start operation.

To use in an absolute position system, refer to "CHAPTER 11 ABSOLUTE POSITION
SYSTEM."
 Notes for setting endless ABS in positioning operation mode
<Notes regarding settings>
(1) Set the electronic gear so that it obtains: PA1_06/07 = 2
n
(n ≥8)
The absolute system encode works as a 34-bit ring counter consisting of 18-bit single-turn
counter and 16-bit multi-turn counter. On the other hand, as the current position output to the
host device via Modbus-RTU is given a 32-bit data, the size must be matched each other
using the electronic gear setting.
(2) Set the parameter PA2_25 (position command format) to "0" (normal PTP).
If set to "1" (endless), current position is reset (but the multi-turn data of the encoder is not
cleared) every time the positioning operation (positioning data operation and immediate
value operation) is started. Therefore, it will be difficult to recognize the current positions from
the host device.
<Notes regarding functions>
(1) The following functions are disabled: hardware OT, software OT and limiter detection.