1-9 Encoder specifications (Absolute encoder)
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Encoder specifications (Absolute encoder)
The absolute encoder used in the SHA series is a multi-turn magnetic absolute encoder. This encoder consists of
17 bit single turn absolute encoder and a 16 bit cumulative counter for detecting the number of total revolutions.
This encoder constantly monitors the absolute machine position and, by means of an external backup battery*
2
, stores the
position regardless of whether the driver or external controller power is turned ON or OFF. Accordingly, once the origin is
detected when the machine is first installed, homing is not required for subsequent power ON operation. This facilitates an
easy recovery after a power failure or machine breakdown.
Additionally, when the power is ON, the single revolution absolute position and the number of revolutions is calculated with
dual-redundant systems and comparison checks are continually performed on the data. This highly reliable design allows for
encoder errors to be self-detected should they ever occur.
In addition, a backup capacitor is installed in the encoder to retain the absolute position data even when the actuator is
disconnected from the driver for the purpose of maintenance, etc. (Internal backup). It is recommended that you replace the
backup battery in the HA-800 driver while the driver is receiving power.
Specifications
Type
*1
Magnetic sensor/electronic battery backup type
(Single rotation optic, multiple revolution magnetic sensor/electronic battery backup
type)
Resolution per motor revolution
17 bits (2
17
: 131,072 pulses)
Maximum cumulative motor shaft
revolutions
16 bits (2
16
: 65,536 revolutions cumulatively)
Maximum permissible motor shaft
rotational speed
7000rpm
Safety/redundancy
・
Check method in which two identical single revolution detectors are compared
・
Check method in which two identical cumulative revolution counters are compared
Backup time by external battery
*2
1 year (when power is not supplied)
Internal backup time
30 minutes (after 3 hours of charge, ambient temperature of 25
℃
, axis stopped)
(For backup while the driver and encoder are disconnected briefly)
*1: Size 20 is equipped with an optical encoder; other models are equipped with a magnetic encoder.
*2 : Battery box is sold separately (Recommended battery is Maxell ER 17/33 battery)
Resolution at the output shaft
Encoder resolution
2
17
（
131,072
）
Reduction ratio
11:1
51:1
81:1
101:1
121:1
161:1
Resolution at the
output shaft
Pulse/rev
1,441,792
6,684,672
10,616,832
13,238,272
15,859,712
21,102,592
Resolvable angle per
pulse (approximate)
Sec.
Approx.
0.9
Approx.
0.2
Approx. 0.12
Approx. 0.1
Approx.
0.082
Approx.
0.061
Absolute position data
[Absolute position] indicates the absolute position within one motor shaft revolution, while [multi revolution]
indicates the number of motor revolutions. The position of the actuator output shaft is obtained by the following
formula:
Position of actuator output shaft = (Absolute po Multi revolution data x Encoder resolution) / Reduction
ratio
Reduction ratio
50:1
80:1
100:1
120:1
160:1
Resolution at the
output shaft
Pulse/rev
6,553,600
10,485,760
13,107,200
15,728,640
20,971,520
Resolvable angle per
pulse (approximate)
Sec
Approx.
0.2
Approx.
0.12
Approx. 0.1
Approx.
0.082
Approx.
0.062
