Yaskawa MP930 - Manual (Page 247)

Absolute Position Detection
7.3.2 Infinite Length Mode Axis
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J Ladder Logic Program for Infinite Length Mode Axis Position
Control
Special ladder logic programs for normal operation and for restarting the system are needed
for absolute Infinite Length Mode Axis position control when an absolute encoder is used as
an Infinite Length Mode Axis.
Normal Operation
1. Check the Zero Point Setting Complete status.
Check to see if monitor parameter Zero Point Setting Complete (IWxx15 bit 3) is ON. If
it is, go to step 2.
If it is not, it means that the pulse position at power OFF, encoder position at power OFF
and all position data was not checked. In that case, restart the system and set up the position
data again or execute the ZSET motion command (zero point setting) to check the position
data all over from the start.
2. Save the pulse position at power OFF and encoder position at power OFF.
Use the customer’s ladder logic program to save the following monitor parameters with
high-speed scan timing at an M register backed up by battery.
Monitor parameter: Encoder Position at Power OFF (All four words at ILxx38/ILxx3A)
Monitor parameter: Pulse Position at Power OFF (All four words at ILxx3C/ILxx3E)
The M register that is used to save the above monitor parameters is structured as shown
below.
MWxxxxx Bit 0 Toggle Buffer Enabled Flag (0: Disabled/1: Enabled)
Bit 1 Toggle Buffer Selection Flag (0: Buffer 0/1: Buffer 1)
Bit 2 Position Data Re-setup Request Flag (0: Complete/1: Request)
MLxxxxx + 1 Not used
MLxxxxx + 2 Buffer 0 Monitor parameter:
Encoder Position at Power OFF Rightmost two words (ILxx38)
MLxxxxx + 4
Encoder Position at Power OFF
Leftmost two words (ILxx3A)
MLxxxxx + 6 Monitor parameter:
Pulse Position at Power OFF Rightmost two words (ILxx3C)
MLxxxxx + 8
Pulse Position at Power OFF
Leftmost two words (ILxx3E)
MLxxxxx + 10 Buffer 1 Monitor parameter:
Encoder Position at Power OFF Rightmost two words (ILxx38)
MLxxxxx + 12
Encoder Position at Power OFF
Leftmost two words (ILxx3A)
MLxxxxx + 14 Monitor parameter:
Pulse Position at Power OFF Rightmost two words (ILxx3C)
MLxxxxx + 16
Pulse Position at Power OFF
Leftmost two words (ILxx3E)
Note Two buffers are needed to save the encoder position and the pulse position at power OFF because the
program may be exited without checking position data at all four words if power is turned OFF during
the high-speed scan.
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