Allen-Bradley micrologix 1500, Руководство пользователя

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Publication 1764-UM001A-US-P
6-2 Using Real-Time Clock and Memory Modules
Writing Data to the Real-Time Clock
When valid data is sent to the real-time clock from the programming device, the
new values take effect immediately.
The real-time clock does not allow you to write invalid date or time data.
RTC Battery Operation
The real-time clock has an internal battery that is not replaceable. The RTC
Function File features a battery low indicator bit (RTC:0/BL), which shows the
status of the RTC battery. When the battery is low, the indicator bit is set (1). This
means that the battery may fail within 14 days and the real-time clock module
needs to be replaced. When the battery low indicator bit is clear (0), the battery
level is acceptable or a real-time clock is not attached.
If the RTC battery is low and the controller is powered, the RTC operates
normally. If the controller power is removed and the RTC battery is low, RTC data
may be lost.
Use the Disable Clock button in your programming device to disable the real-time
clock before storing a module. This decreases the drain on the battery during
storage.
Table 6.1 RTC Battery Life Expectancy
Battery State Temperature Time Duration
Operating 0°C to +40°C (+32°F to +104°F)
5 years
(1)
(1) The operating life of the battery is based on 6 months of storage time before the real-time clock is used.
Storage -40°C to +25°C (-40°F to +77°F) 5 years minimum
+26°C to +60°C (+79°F to +140°F) 3 years minimum
ATTENTION
!
Operating with a low battery indication for more than 14 days
may result in invalid RTC data if controller power is lost.