IAI America SSEL - Manual (Page 387)

365
Appendix
2. Absolute-Data Backup Battery for Absolute Encoder
If the SSEL controller is to drive/control an absolute type actuator, an absolute-data 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-data 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-data 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
qC, 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 a surrounding air
temperature of 40
qC with the controller powered up 50% of the time.
To replace the absolute-data backup battery, disconnect the battery connector at the bottom of the
controller, and change the battery in the battery holder with a new battery.
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 a surrounding air temperature of
20
qC 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 periods should be reduced to 70% at 20
qC or to 60% at 40qC.
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).
To prevent the risk of data loss, you can use the PC software to evacuate the data in the SRAM to the
flash ROM and then reload the flash ROM data to the SRAM after a new battery is installed.
The absolute-data 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.