MAN1256-05-EN_EXLW_XLWP_UM
November 10, 2021
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21.5 OCS Battery Charging Cycle
There are various charging states that are executed based on battery temperature, level
of battery charge, and self-test results. The battery temperature can be determined by
checking the CPU temperature in the controller System Menu: View Battery Status or by
monitoring System Register %SR195.
The battery temperature is equal to the CPU temperature minus 30°C.
NOTE: Refer to Table 20.1 for charge states and definitions.
1.
When power is applied to the OCS, the unit always goes to State 11; Waiting, for the
first two minutes.
2.
After two minutes have expired, the OCS will begin charging the battery based on
battery temperature. In this step, charging will ensue even if the battery is already
fully charged.
In this step charging does not ensue if the battery temperature is outside of the
acceptable hot or cold limits.
3.
The battery is charged fully to 4.2 volts in the Normal Charging or Cold Charging
states or to 4.1 volts in the Hot Charging state.
4.
Once fully charged to 4.2 volts, state 0, the Wait Discharging state is executed,
state 12. The battery is allowed to discharge to 4.0 volts for however long that
takes. Powering up the OCS will reset the charge cycle to step 1.
5.
If the battery was charged to 4.1 volts under state 2, Hot Charging; 4.1 volts is
maintained until Normal or Cold Charging can be executed.
Note: If the battery voltage is too low, less than 2.5 volts, or if the battery is missing,
charging is suspended. In this condition, the OCS unit fails self-test. Diagnostics will
show a battery warning. %SR55.13 will be ON.
Note: If the battery is not missing and the voltage is 2.5 volts or greater but will not fully
charge in 8 to 40 hours, the charge cycle is suspended for 5 minutes and then tried
again.
Note: Because the OCS is designed to maintain the Real Time Clock for a year or more in a
powered down state, this translates as; the battery requires up to 8 to 40 hours of
recharging time in a year.
