IAI America SCON-C - Manual (Page 193)

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Appendix
2.1 Absolute-encoder Backup Battery
If the SCON controller is to drive/control an absolute type actuator, an absolute-encoder backup battery must be
installed in the controller.
An absolute encoder is designed to retain rotation data and detect rotations using the power supplied from the
absolute-encoder backup battery, even when the controller’s control power is not supplied. This allows the
controller to resume positioning control immediately after the controller power is restored, without performing
home return.
The recommended replacement interval for the absolute-encoder backup battery is two years. This may be a
little misleading. It means that if the battery is left at a surrounding air temperature of 40
C, it will retain the
stored data for two years. In normal operating conditions, the battery can retain data for a longer period. As a
guide, the battery will last for around four years if the controller is used at an ambient temperature of 40
C with
the controller powered up 50% of the time.
To replace the absolute-encoder backup battery, unplug the battery connector at the bottom of the controller and
replace the battery in the battery holder.
It is recommended that the battery be replaced regularly in accordance with the frequency/duration of usage.
The battery must be replaced as soon as the controller’s battery voltage monitor function generates a battery
voltage low alarm.
After an alarm is detected, a battery error will occur in approx. 10 days at an ambient temperature of 20
C if the
power is supplied to the controller continuously. Once a battery error occurs, operations can no longer be
performed unless the battery is replaced and an absolute reset is performed.
If the controller is not operated, the above period should be reduced to 70% at 20
C or to 60% at 40C.
The controller is designed so that the data will not be lost for at least 15 minutes without a battery if the controller
is not detecting a battery error. Remember to complete the battery replacement within 15 minutes (i.e., the
controller should not be without a battery for more than 15 minutes).
The absolute-encoder backup battery is replaced differently depending on whether a battery error has generated
or not. If an error has not been detected, only the battery needs to be replaced and an absolute reset is not
required. If an error has been detected, an absolute reset will be required.