Yaskawa MP920 Motion Module - Manual (Page 210)

5 SVA Module Specifications and Handling
5.4.2 Motion Setting Parameters
5-68
„ Supplemental Explanation 3
1. Procedure for Using the Zero Point Offset
a) Applications where Absolute Encoder Rotates in One Direction
The zero point position offset can be used in applications where the absolute encoder
rotates in one direction by using OL††06: Zero Point Offset Setting in the motion
parameters and creating a user program that will control the absolute position.
b) Initializing the Absolute Encoder
A pulse cannot be reset within one rotation simply by shorting R-S.
For example, an initial incremental pulse corresponding to 0.5 rotations will be sent
even though the absolute encoder is reset (R-S shorted) if the Servomotor stops at
95.5 rotations.
Consequently, position data corresponding to 0.5 rotations rather than 0 will be indi-
cated at IL††08: Position Monitor.
Set the following in order to set the position monitor to 0.
• Preconditions
Initialize the absolute encoder (short R-S), restart the MP920, and then send a
provisional 120 initial incremental pulses. A value of 120 will appear at the posi-
tion monitor.
• Procedure
The position can be adjusted with the Zero Point Offset. If the zero point offset is
set to -120, the position monitor will show “0.”
The value set at the Zero Point Offset will be reset to “0” if the MP920 is turned
OFF, so we recommend setting the parameter with Drawing A (initial processing
drawing).
Example 1: Set DWG.A as follows:
OLC006 - 0000000120 ⇒ OLC006
Example 2: Set DWG.A as follows:
7 Machine Coor-
dinate System
Zero Point Off-
set Setting
(ABSOFF) OL††06
-2 31 to 2 31 -1
Position data can be shifted by the value set in this regis-
ter. See 1 of Supplemental Explanation 3. The parameter
is valid during RUN operation, but set it while the system
is OFF.
This register contains data used by SVA Modules for
position control and the following movements are
affected if this register is set incorrectly. Check to see if
the data is set correctly prior to starting operation.
Obstructions may damage tools and lead to personal
injury if this check is not performed.
Refer to 2 of Supplemental Explanation 3. 0
9 Not used. OL††08 Set to “0.” 0
Table 5.6 Motion Setting Parameters (cont’d)
No. Name Register
Number
Setting Range/
Bit Name
Description Factory
Setting