5 Operation
62 SD780 Series Servo Technical Manual
5.1.8 Multi-turn Absolute Encoder
When using a multi-turn absolute encoder, an absolute value detection system can be constructed
by a host device. With the absolute value detection system, it is not necessary to perform an origin
return operation every time the power is turned on. In order to save the position data of the
absolute encoder, a battery unit needs to be installed. Install the battery on the battery unit of the
encoder cable with the battery unit. When using an encoder cable without a battery pack, install
the battery in the host device. The battery voltage is 3.2V
～
4.5V. If the battery voltage is lower
than 3.2V, a battery under-voltage alarm (ER.830) will appear. Generally, 3.6V/3.7V lithium
batteries are used.
Related parameters setting:
Function
code
Parameter
Rang
e
Default
s
Unit
Communication
address
When enabled
Pn040
Method to
use absolute
encoder
0
～
1
0
－
0x0040
After restart
0- Use an absolute encoder as an absolute encoder: If the motor is an absolute
multi-turn encoder, setting this parameter to 0 can use the multi-turn absolute
function. This function must be used with the encoder cable with battery, otherwise
the servo will alarm (ER.810).
1- Use an absolute encoder as an incremental encoder: When used as an
incremental encoder, the power-off position won’t be recorded and warning or
alarm, corresponding to multiple revolutions, won’t happen either when the battery
is under-voltage or the drive is de-energized.
Pn041
Absolute
encoder
battery
warning/warn
ing selection
0
～
1
0
－
0x0041
After restart
0- Set the low battery voltage as a fault: The driver powers up/resets for 4
～
9
Overload detection
time
Torque command%
100%
200%
10
0% overload alarm detection curve
50% overload
alarm detection
curve