Page 4–6 2104349 rev. AD4.6 Changing the G4 EX ClockWhen any measurement applications are instantiated on the G4 EX, changing theclock could affect the time when log period entries are made. To protect theintegrity of the accounting audit trails, the G4 EX handles these types of clockchanges as follows:4.6.1 Clock Change Not Crossing an Hour BoundaryWhen the next log period entry is made, the clock is not altered.Example: If the present time is 4:14 pm and the clock is changed to 4:05 pm ofthe same day, the daily flow record is the same. Entry reflects averagesaccumulated over a 70 minute time period (15 minutes plus 55 minutes).4.6.2 Forward Clock Change Crossing an Hourly BoundaryForces a log period entry for part of the hour that has accumulated since the lasthourly entry. The G4 EX then advances to the newly defined data flow recordboundary and begins maintaining the balance of the day’s data in a newly definedboundary.Example: If the present time is 4:55 pm and the clock is changed to 5:05 pm ofthe same day, the entry reflects only a 55 minute average accumulation. A newflow record is then written. This period is also based on a 55 minute accumulation.4.6.3 Backward Clock Change Crossing an Hourly BoundaryHourly entry is made for part of the hour that has accumulated since making thelast hourly entry. This is the same as a Forward Clock Change Crossing an HourlyBoundary. The G4 EX advances to a new day’s data flow record and maintainsthe balance of the day’s data in a new record.Example: If the present time is 5:05 pm and the clock is changed to 4:55 pm ofthe same day, the log period entry reflects only a five minute averageaccumulation. A new flow record is then written. This log period is based on a 60minute accumulation.A backward clock change uses two records to maintain dataintegrity. This assures that previously recorded data is notoverwritten.If it is necessary to make small backward time changes ofless than one (1) hour, the user should wait until the currenthour has progressed far enough to make a change that doesnot cross an hour boundary.4.7 Replacing the G4 EX battery PackThis chapter presents the procedures for removal and installation of the G4 EXbattery pack that is located within the 6270 OEU. To access the battery pack,open the door (see Figure 4–3). The battery pack is located in the upper portion ofthe chamber.
