Yaskawa MP920 Motion Module - Manual (Page 60)

2 Motion Control
2.3.1 Prerequisites for Position Control
2-34
With the position reference for an infinite length axis, the present travel distance (incremen-
tal travel distance) is added to the previous position reference (OL††12), and the position
reference (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 2.15 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 addition
mode) Sets the present travel distance value (increment) added to the previ-
ous 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 designation) 0
(Absolute position
mode) Sets the position buffer number.
The absolute position must be stored in advance in the position
buffer with the specified number.
1234
1
2
3
4
99
256
Position buffer
99
OL 12
Position buffer number
(1 to 256)
1234 of position buffer
99 is used as the ab-
solute position.