Absolute Position Detection System; Outline; Absolute Position System Coordinate System - Mitsubishi Electric MELDAS C6 Instruction Manual

4. Absolute Position Detection System

4.1 Outline

The absolute position detection function detects the machine movement amount while the power is
OFF. This allows automatic operation to be started without carrying out zero point return after the
power is turned ON. This function is reliable as it carries out a mutual check of the feedback amount
from the detector, and checks the absolute position unique to the machine, etc.
To carry out absolute position detection, the machine zero point must be positioned, and the absolute
position must be established. This machine uses only the dogless-type absolute position detection.
(1) Dogless-type absolute position detection
The absolute position is established by setting a random coordinate at a random position without
using the dog.
The basic position can be determined with the following two methods.
• Machine end stopper method
• Marked point alignment method
For the machine end stopper method, the manual initialization and automatic initialization
methods can be used.
(2) Dog type absolute position detection
The absolute position is established by executed dog type zero point return.
The validity and method of the absolute position detection system can be selected with parameters for
each axis. Note that the servo amplifier and detector must have the absolute position detection
specifications.

4.2 Absolute Position System Coordinate System

Using the mechanical basic position (machine end or origin point) or the electrical basic position
(machine end or grid point just before origin point) as the absolute position origin point, the basic
machine coordinate system zero point is set at the position obtained by reversing the "ZERO"
parameter sign. The reference point is set at the "G53ofs" parameter from the basic machine
coordinate system's zero point.
"ZERO"
"G53ofs"
(Note) Whether to use the mechanical basic position or electrical basic position as the absolute
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4. Absolute Position Detection System
Basic machine
coordinate system
Reference point
Dogless absolute position coordinate system
: Coordinate value of absolute position origin point looking from basic machine
coordinate system zero point (ABS. POSITION SET screen "#2 ZERO").
: Coordinate value of reference point looking from basic machine coordinate system zero
point (parameter "#2037 G53ofs").
position origin point is selected with parameter "#2059 zerbas".
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4.1 Outline
"ZERO"
G53ofs
III - 16
Absolute position
origin point