Casella CEL CEL-393 - Manual (Page 39)

Event mode may be re-entered only by switching the instrument OFF
and ON again, having first interrogated any results in the memory.
Resets
Current period data is reset by key sequence 0R, and all data including
memories, delay start flag, and period time by 0C. However, the main
clock remains set to real time. To prevent results taken with different
frequency or time weightings from being confused in the memory, it will
be reset if either the detector or weightings are changed. Therefore, it is
important that the memory be read before the measurement configora-
tion is changed in this manner.
Clock
A quartz crystal regulated clock is provided, which is arranged on a 24
hour format in hours and minutes. The clock runs on beyond 24.00 hours
so that elapsed days may be indicated by the instrument. A maximum of
99 hours 59 minutes (4 days 3 hours 59 minutes) can be registered
before returning to 00.00 and commencing again. The clock will default
to 00.00 at switch on, so it will indicate elapsed time, or may be set to
indicate real time. All time functions (time, period and delayed start) are
synchronised to the next minute forward, and will therefore operate from
the same effective time if entered within the same minute.
Delayed Start Timer
This is arranged in the same format as the main clock, and allows the
data stored to be gated off for up to 99 hours 59 minutes (4 days 3 hours
and 59 minutes). When the main clock passes the delay time, the period
measurements commence, with results being stored if the instrument is
configured in the 'environmental' memory mode only. Note that period
reset (0R), or changing the period or main clock settings cancel the
operation of the delay start function but do not remove it from the display.
4.4 Auxiliary Outputs
393 Handbook /35.