Yaskawa MP2200 Machine Controller - Manual (Page 397)

7.3 Using an Absolute Encoder
7-13
7.3 Using an Absolute Encoder
This section explains precautions regarding use as well as the procedure for setting the zero
point when using an absolute encoder.
7.3.1 Finite Length Axis
( 1 ) Overview
An absolute encoder stores the multiturn data in internal memory backed up by battery. This way the
zero point of the coordinate system can be determined without the zero point return operation when
the system is started up. Once the system is started, the encoder functions just like an incremental
encoder.
Unfortunately, the maximum multiturn data is
±99999 for the Σ Series and -32768 to 32767 for the
Σ -II /III Series. If system power is turned ON when the multiturn data exceeds these limits, the
MP2200/MP2300 position will not be the same before and after power is turned ON.
The multiturn data for the encoder functions as illustrated below.
[ a ] Σ Series
[ b ] Σ-II or Σ-III Series
Therefore, be sure to observe the following precautions when using an absolute encoder for a finite
length axis.
• Be sure to initialize the encoder prior to setting the zero point.
• Use the absolute encoder within the range of the multiturn data.
The actual machine operating range may vary depending on parameters like the gear ratio.
• Do not change the Zero Point Offset (OL††48) while operating a machine with a finite length axis.
Otherwise the machine may be damaged or an accident may occur.
CAUTION
Reverse limit Forward limit
Reference
position
Reverse
direction
Forward
direction
0
( −99999 rotations) (+99999 rotations)
Reverse limit Forward limit
Reverse
direction
Forward
direction
0
( −32768 rotations) (+32767 rotations)
Reference
position
INFO