IAI America XSEL-QX - Manual (Page 445)

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Appendix
2. Absolute-Encoder Backup Battery
If the X-SEL controller is to drive an absolute-type actuator, an absolute-encoder backup battery must be
installed in the robot or 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.
<Backup Time>
The recommended replacement interval for the absolute-encoder backup battery is two to three years. It
means that if the battery is left at a surrounding air temperature of 40
qC (with the power not supplied at all),
it will retain the stored data for two to three years. In normal operating conditions, the battery can retain
data for a longer period. As a guide, the battery will last for around twice the specified period if the
controller is used at a surrounding air temperature of 40
qC where the controller powered up 50% of the
time.
<Battery Replacement>
It is recommended that the battery be replaced regularly in accordance with the frequency/duration of
controller 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 encoder reset is performed.
If the controller is not operated at all, the above periods should be reduced to 70% at 20
qC or to 60% at
40 qC.
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.
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 yet, the battery needs to be replaced and the absolute
encoder must be reset. If an abnormal absolute-encoder backup battery voltage error has been detected
(error No. 914, CA2), an absolute encoder reset will be required.