Smart Batteries; Smart Battery Operation; Ic695Acc302 - Emerson PACSystems RX3i Manual

Battery & Energy Pack Manual
GFK-2741J
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The use of a non-smart battery or a CPU not on this list will result in the low battery detection
bits being unreliable.
Low/failed battery conditions are indicated by CPU LED operation and %S status bits. For
details, refer to Diagnostics in the PACSystems RX7i & RX3i CPU Reference Manual, GFK-
2222.
2.4

Smart Batteries

2.4.1

Smart Battery Operation

The battery output voltage is > 2.5 V when the battery is operating in its good state. At the
end of the battery good period, the battery output drops to < 2.5 V for the battery low state.
The period for the battery low state is 15 days for all CPU models. Once battery output
voltage drops to < 2.5V, compatible PACSystems CPUs detect this as a battery low
condition; a Low Battery fault is logged in the Controller fault table and the red Battery LED
on the CPU starts blinking.
Once the low battery state is active, the user has 15 days of accumulative battery backed
energy left for CPU RAM retention during power loss. Since the low battery period may start
while the PLC is powered down and faults cannot be logged in this state, the low battery
fault date is unlikely to indicate the starting point of the 15-day count down. System power
shutdowns should not exceed 15 days as the battery voltage may drop to 0 V, resulting in
the loss of CPU RAM memory contents.
Figure 1: Low Battery Countdown Example
The Battery Low period of 15 days starts at Point T1, but the low battery fault is logged at
Point T2, when the controller is powered ON. The user should be aware that the Low Battery
fault timestamp does not indicate the start of the 15-day Battery Low period.
2.4.2

IC695ACC302

Batteries
IC698CRE040-Hx and later hardware revisions with firmware revision 6.75 or later
Chapter 2
Oct 2019
8