Mitsubishi Melsec-Q QD75D1, User Manual

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12 - 68
MELSEC-Q
12 CONTROL SUB FUNCTIONS
[4] Control precautions
(1) 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.
(2) 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.
Condition 1. Number of output pulses
a) 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]
≤
[32768 (number of feedback pulses)-1]
b) Pulses are positive in the address increasing direction from the OP, and
negative in the address decreasing direction from the OP.
Unit:
μ
m
OP
0
-214748364.8
214748364.7
Negative pulse outputs Positive pulse outputs
c) The number of output pulses varies with the number of feedback pulses as
indicated below:
• When the number of feedback pulses is 8192 (pulse):
-268435456 (pulse) to 268435455 (pulse)
• When the number of feedback pulses is 16384 (pulse):
-536870912 (pulse) to 536870911 (pulse)
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.
Condition 2. Positioning address
a) The following positioning addresses can be specified on the QD75:
• When the unit is mm: -214748364.8 (
μ
m) to 214748364.7 (
μ
m)
• When the unit is inch: -21474.83648 (inch) to 21474.83647 (inch)
• When the unit is pulse: -2147483648 (pulse) to 2147483647 (pulse)
• When the unit is degree: 0
°
to 359.99999
°