Yaskawa MP920 User's Manual Design - Manual (Page 148)

4 Motion Control
4.3.1 Prerequisites for Position Control
4-34
With the position reference for an infinite length axis, the present travel distance (incremental
travel distance) is added to the previous position reference (OL††12), and the position ref-
erence (OL††12) is reset. The position reference (OL††12) must not be set in the range
of 0 to (infinite length axis reset position
− 1).
Position Buffers
The position buffers are a collection of position data stored in the SVA Module, and a maxi-
mum of 256 points can be stored for each axis. They are used for the position data when
POSITIONING and other motion commands are executed. Continuous operation is enabled
by storing the position data in advance, and by using a simple program that only specifies the
points.
Table 4.14 Position Reference Value Selection
Position Reference
Value Selection
(Bit 12 of
OW††01)
Position Reference
Type
(Bit 14 of
OW††01)
Position Reference (OL††12)
0
(Direct designation) 0
(Absolute position
mode) Sets the absolute position. (Moves to the setting position.)
Example: OL††12
←10000
OL††12 ←20000
1
(Incremental addi-
tion mode) Sets the present travel distance value (increment) added to the previous value of
OL††12.
OL††12
← Previous OL††12 + Incremental travel distance
Example: When the previous OL††12 = 1,000 and the present travel distance is
500, then: OL††12 ← 1000 + 500 = 1500
1
(Indirect designa-
tion) 0
(Absolute position
mode) Sets the position buffer number.
The absolute position must be stored in advance in the position buffer with the spec-
ified number.
1234
99
OL 12
1
2
3
4
99
256
.
.
.
.
.
.
.
.
.
(1 to 256)
Position buffer
Position buffer number
1234 of position buffer
99 is used as the ab-
solute position.