Changing Ngc Clock; Clock Change Not Crossing A Log Period Boundary; Forward Clock Change Crossing A Log Period Boundary; Backward Clock Change Crossing A Log Period Boundary - ABB NGC8206 User Manual

4) If Lithium Battery Status reads "Low Voltage" or "Not Connected", then the
lithium battery should be connected or replaced prior to removing power from the
unit. See instructions later in the chapter,

5.10 Changing NGC Clock

When measurement streams are instantiated on the PGC, changing the clock
could affect the time when log period entries are made. To protect the integrity of
accounting audit trails, the NGC handles these types of clock changes as follows:

5.10.1 Clock Change Not Crossing a Log Period Boundary

When the next log period entry is made, the clock is not altered.
Example: If the present time is 4:15 p.m. and the clock is changed to 4:05 p.m. of
the same day, the daily flow record is the same. The entry reflects the
accumulation over a 70 minute time period (15 minutes plus 55 minutes).

5.10.2 Forward Clock Change Crossing a Log Period Boundary

This forces a log period entry for part of the log period that has accumulated since
the last log period entry. NGC then advances to a new data flow record and
begins maintaining the balance of the day's data in a newly defined boundary.
Example: If the present time is 4:55 p.m. and the clock is changed to 5:05 p.m. of
the same day, the entry reflects only a 55 minute average accumulation. Then a
new flow record is written and this period is also based on a 55 minute
accumulation.

5.10.3 Backward Clock Change Crossing a Log Period Boundary

This forces a log period entry for part of the log period that has accumulated since
the last log period entry. This is the same as for a forward clock change crossing
an hourly boundary. NGC advances to a new day's data flow record and maintains
the balance of the day's data in a new record.
Example: If the present time is 5:05 p.m. and the clock is changed to 4:55 p.m. of
the same day, the log period record entry reflects only a 5 minute average
accumulation (5:00 to 5:05). Then a new flow record is written and this log period
is based on a 5 minute accumulation (4:55 to 5:00).

5.11 Replacing Calibration or Carrier Gas Bottle(s)

When calibration or carrier gas bottle(s) require replacement, use the following

instructions.

2101510 Rev. AG
Replacing Lithium
Examples are based on a 60 minute Log Period.
A backward clock change uses two (2) daily records to
maintain data integrity. This assures that previously recorded
data is not overwritten.
If it is necessary to make small backward time changes, less
than one (1) hour, the user should wait until the current hour
has progressed far enough to make a change that does not
cross an hour boundary.
Battery.
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