Mitsubishi Electric MELSEC-L LD75P User Manual page 570

6.
The servo amplifier turns ON the ABS transmission data ready (ABST) and prepares for the next
transmission. After that, procedures 3. to 6. are repeated until the data corresponding to 32bits
and the checksum corresponding to 6bits are sent.
7.
After the sum check, the LD75 turns OFF the ABS transfer mode (ABSM). If the ABS transfer mode
(ABSM) is turned OFF during the data transmission, the ABS transfer mode will be interrupted.
(4) Control precautions
• When an absolute position detection system is constructed, absolute position restoration must be made at
least once after power supply on or resetting. Also, the servo amplifier does not switch on unless the
absolute position restoration is completed.
• For use of positioning in an absolute position detection system, the following controls cannot be carried out:
Limitless-feed control which exercises control only in the fixed direction, e.g. turntable
Control where the movement amount from the OP address exceeds the range of the following conditions 1
and 2
When performing positioning in an absolute position detection system, use it in the range which satisfies
Conditions 1 and 2 given below.
In the range which does not satisfy Conditions 1 and 2, positioning cannot be used in the absolute position
detection system since the normal current value cannot be provided during absolute position restoration.
(a) Condition 1. Number of output pulses
• Indicates the number of pulses that may be output to a servo amplifier when an axis is to be positioned
from the OP in an absolute position detection system.
In the absolute position detection system, pulses within the range of the following expression can be
output to the servo amplifier.
[-32768  (Number of feedback pulses)]  [Number of output pulses]
[Number of output pulses]  [32768  (Number of feedback pulses) - 1]
• Pulses are positive in the address increasing direction from the OP, and negative in the address
decreasing direction from the OP.
• The number of output pulses varies with the number of feedback pulses as indicated below:


When the electronic gear of the servo amplifier is used, the electronic gear ratio must be considered. The
actual range of the number of output pulses is the value of the range of output pulses above multiplied by
the inverse number of the electronic gear ratio.
(b) Condition 2. Positioning address
The following positioning addresses can be specified on the LD75:
• When the unit is mm: -214748364.8 to 214748364.7 (m)
• When the unit is inch: -21474.83648 to 21474.83647 (inch)
• When the unit is pulse: -2147483648 to 2147483647 (pulse)
• When the unit is degree: 0 to 359.99999
568
-214748364.8
Negative pulse outputs
When the number of feedback pulses is 8192 (pulse): -268435456 to 268435455 (pulse)
When the number of feedback pulses is 16384 (pulse): -536870912 to 536870911 (pulse)
OP
0
214748364.7
Positive pulse outputs
Unit: μm