Woodward MicroNet TMR 5009, Installation/Hardware Manual

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5009 Installation/Hardware Manual 85580V2
6 Woodward
The CPU module has a battery to power the Real Time Clock, even when power
to the control is off. This battery is not user-replaceable. During normal operation
onboard circuitry keeps the battery charged at all times. Once the battery is fully
charged (16 hours) the battery will continue to run the clock for a minimum of
three months without power to the control. Should the CPU not be powered for
several months and the battery loses it’s charge, the Real Time Clock will need
to be set once the CPU is powered up. The module will automatically recharge
the battery once powered. See the battery specifications in Chapter 6.
Figure 2-3. CPU Module
CPU Port Filter Assembly
The CPU module’s front serial port is sensitive to cable noise. Noise form
external sources (relays, breakers, ESD, etc.) couples onto the attached serial
cable, and into the CPU. Noise of this nature can cause temporary CPU failures.
Three filter assemblies (one per CPU) are provided with each system to protect
the CPU from external system noise. These filter assemblies are shipped
separately from the control and can be easily installed if use of the CPU port is
required.