Semi-Absolute - Yamaha RCX240 User Manual

11. "MANUAL" mode
11.8.2

Semi-absolute

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"Semi-absolute" is the name for a simple absolute scale used in the YAMAHA linear single-axis
robot PHASER series. Robots with this simple absolute scale have a quick absolute search function
that utilizes our unique method to automatically perform an absolute search on the position
detection scale when return-to-origin starts. This function allows detecting the absolute position
with just a minimal movement.
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Using this scale drastically reduces the time needed for return-to-origin operation by PHASER
series robots, especially those with long-stroke movements.
■ Absolute search
Absolute search (also called "absolute reset") includes the sensor method and stroke end
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detection method. Absolute search movement differs depending on the robot position from
which absolute search starts. (In the sensor method, absolute search movement depends on
whether the origin sensor turns on during absolute search. In the stroke end detection method,
absolute search movement depends on whether or not the stroke end is detected during
absolute search.)
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After the absolute search is complete, the origin position is set to zero position on the simple
absolute scale.
n
NOTE
Zero position can be shifted by using the "Origin shift" parameter of the axis
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parameters.
Refer to "11.8.3 Return-to-origin procedure" for instructions on how to perform return-to-origin.
l Sensor method: When the origin sensor does not turn on during absolute search
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l Stroke end detection method: When the stroke end is not detected during absolute search
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q Upon starting return-to-origin, the robot moves in the return-to-origin direction to start an
absolute search.
The robot moves to a maximum position A. The maximum distance that the robot can move
to position A from the absolute search start position is 76mm.
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w The robot moves back from position A, determines the current position, and then stops. The
stop position does not exceed the absolute search start position.
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Chapter 4 OPERATION
Absolute search (1)
Absolute search start position
A
Max. 76mm
q
w
Return-to-origin direction