Allen-Bradley AADvance, Руководство пользователя

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48 Rockwell Automation Publication ICSTT-RM448J-EN-P - April 2018
Chapter 2 The AADvance Safety Controller
Processor Back-up Battery
The 9110 processor module has a back-up battery that powers its internal Real
Time Clock (RTC) and a part of the volatile memory (RAM). The battery
only supplies power when the processor module is no longer powered from the
system power supplies. The specific functions that the battery maintains on
complete loss of power are:
• Real Time Clock - The battery supplies power to the RTC chip itself.
• Retained Variables - Data for retained variables is stored at the end of
each application scan in a portion of RAM, backed up by the battery. On
restoration of power' the retained data is loaded back into the variables
assigned as retained variables for use by the application.
• Diagnostic logs - The processor diagnostic logs are stored in the portion
of RAM backed by the battery.
The battery has a design life of 10 years when the processor module is
continually powered; for processor modules that are un-powered, the design
life is up to 6 months. Battery design life is based on operating at a constant
25°C and low humidity. High humidity, temperature and frequent power
cycles will shorten the operational life of the battery.
Low Battery Alarm
A variable is available in the Workbench that can be set up and report the
battery status. It will give an alarm and set a warning light on the processor
front panel when the battery voltage is low.
Disabling the Low Battery Alarm
For applications that do not require Real Time Clock functionality, or there
are specific constraints, for example, the controller is in an inaccessible
location, that make it necessary to remove the battery when the system is
installed and set up, the battery failure alarm can be disabled at the Workbench.