IAI America XSEL-QX - Manual (Page 443)

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Appendix
Battery Backup Function
The X-SEL controller uses the following two types of batteries.
x System-memory backup battery
This coin battery is used to back up the position data, SEL program variables, etc., in the controller.
Each controller ships with the system-memory backup battery.
x Absolute-encoder backup battery
A separate battery is used to retain the absolute encoder’s rotation data, so that the motor rotation data
can be retained/refreshed when the controller power is cut off. A controller specified with an absolute-
type actuator is shipped with the absolute-encoder backup battery.
Each battery is explained in details below.
1. System-Memory Backup Battery
So that the various data stored in the system memory (SRAM) inside the X-SEL controller can be retained
even after the power has been cut off, a coin battery holder is provided in the panel on the front face of the
controller to enable backup operation.
The data backed up in the system memory (SRAM) includes SEL global data, position data, coordinate
system definition data and user-data backup memory of the controller with increased memory size (with
gateway function). The above data can be retained even after the power has been cut off.
Note, however, that position data and user-data backup memory are also stored in the flash ROM, so if
the operation is always resumed using the data in the flash ROM following a cutoff of power or software
reset, you need not install a battery. (Other parameter No. 20 must be set to “0” (no backup memory).)
Note: On controllers with increased memory size (with gateway function), the position data to be backed
up are position Nos. 1 to 10000. To retain position data of position No. 10001 onward in the event
of power cutoff, write the position data to the flash ROM before the power is cut off.
The system-memory backup battery uses a coin battery (Model CR2032). Since the retention
characteristics of this battery will vary significantly depending on the storage temperature and operating
environment, due caution must be exercised when handling the battery.
Although products similar to this battery are readily available in supermarkets, convenience stores, etc.,
batteries by other manufacturers may offer different retention characteristics. To maintain consistency, use
a battery by the same manufacturer whenever possible.
<Backup Time>
The recommended replacement interval for the system-memory backup battery is one and a half years.
This may be a little misleading. It means that if the battery is left at a surrounding air temperature of 40
qC
for one and a half years, it will retain the stored data for one and a half years. In normal operating
conditions, the battery can retain data for a longer period. As a guide, the battery will last for around three
years if the controller is used at a surrounding air temperature of 40
qC with the controller powered up 50%
of the time.