5.9 Absolute Encoders
5-61
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5.9
Absolute Encoders
If using an absolute encoder, a system to detect the absolute position can be designed for use with the host
controller. By using an absolute position detection system, an operation can be performed without a zero point
return operation immediately after the control power supply is turned ON.
A battery case is required to save position data in the absolute encoder.
The battery is attached to the battery case of the encoder cable.
If an encoder cable with a battery case is not used, install a battery to the host controller.
Set Pn002.2 to 0 (factory setting) to use the absolute encoder.
The SEN signal and battery are not required when using the absolute encoder as an incremental encoder.
PROHIBITED
• Do not install batteries in both the host controller and battery case. It is dangerous because that sets up a
loop circuit between the batteries.
Parameter
Meaning
When
Enabled
Classification
Pn002
n.
0
[Factory setting] Uses the absolute encoder as an absolute encoder.
After restart
Setup
n.
1
Uses the absolute encoder as an incremental encoder.
The rotational serial data output range for a large-capacity
Σ
-
V
-series absolute position
detecting system is different from the range for previous
Σ
-series systems. As a result,
the infinite-length positioning system of the
Σ
servo drives must be changed for use with
Σ
-
V
large-capacity servo drives. Be sure to make the following system modifications.
∗
This is the resolution for a motor capacity of 22 kW or higher.
Series (Models)
Absolute
Encoder
Resolution
*
Output Range
of Rotational
Serial Data
Action when Limit Is Exceeded
Σ
Series
(SGDB)
12-bit
15-bit
-99999 to
+ 99999
• When the upper limit (+99999) is exceeded
in the forward direction, the rotational
serial data will be 0.
• When the lower limit (-99999) is exceeded
in the reverse direction, the rotational serial
data will be 0.
Σ
-
II
Series
(SGDM/SGDH)
or large-capacity
Σ
-
V
Series
(SGDV)
17-bit
20-bit
-32768 to
+ 32767
• When the upper limit (+32767) is exceeded
in the forward direction, the rotational
serial data will be -32768.
• When the lower limit (-32768) is exceeded
in the reverse direction, the rotational serial
data will be +32767.
Note: If you change the multiturn limit set-
ting (Pn205), the operation will be different
for both forward and reverse rotation. (Refer
to
5.9.6 Multiturn Limit Setting
.)
