Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 100)

Operating Instructions Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 82
6.7.2.6. Sample Period and Report Period
The DAS defines two principal time periods by which sample readings are taken and permanently
recorded:
 SAMPLE PERIOD: Determines how often DAS temporarily records a sample reading of the
parameter in volatile memory. The SAMPLE PERIOD is set to one minute by default and generally
cannot be accessed from the standard DAS front panel menu, but is available via the instruments
communication ports by using APICOM or the analyzer’s standard serial data protocol.
SAMPLE PERIOD is only used when the DAS parameter’s sample mode is set for AVG, MIN or
MAX .
 REPORT PERIOD: Sets how often the sample readings stored in volatile memory are processed,
(e.g. average, minimum or maximum are calculated) and the results stored permanently in the
instruments Disk-on-Chip as well as transmitted via the analyzer’s communication ports. The
REPORT PERIOD
may be set from the front panel.
If the INST sample mode is selected the instrument stores and reports an instantaneous reading
of the selected parameter at the end of the chosen REPORT PERIOD
In AVG, MIN or MAX sample modes, the settings for the SAMPLE PERIOD and the REPORT PERIOD
determine the number of data points used each time the average, minimum or maximum is calculated,
stored and reported to the com ports. The actual sample readings are not stored past the end of the of
the chosen REPORT PERIOD.
Also, the SAMPLE PERIOD and REPORT PERIOD intervals are synchronized to the beginning and end
of the appropriate interval of the instruments internal clock.
 If
SAMPLE PERIOD were set for one minute the first reading would occur at the beginning of the next
full minute according to the instrument’s internal clock.
 If the REPORT PERIOD were set for of one hour the first report activity would occur at the beginning
of the next full hour according to the instrument’s internal clock.
EXAMPLE: Given the above settings, if DAS were activated at 7:57:35 the first sample would
occur at 7:58 and the first report would be calculated at 8:00 consisting of data points for 7:58.
7:59 and 8:00.
During the next hour (from 8:01 to 9:00) the instrument will take a sample reading every minute
and include 60 sample readings.
When the STORE NUM. SAMPLES feature is turned on the instrument will also store how many sample
readings were used for the AVG, MIN or MAX calculation but not the readings themselves.
REPORT PERIODS IN PROGRESS WHEN INSTRUMENT IS POWERED OFF
If the instrument is powered off in the middle of a REPORT PERIOD, the samples accumulated so far
during that period are lost. Once the instrument is turned back on, the DAS restarts taking samples and
temporarily them in volatile memory as part of the REPORT PERIOD currently active at the time of
restart. At the end of this REPORT PERIOD only the sample readings taken since the instrument was
turned back on will be included in any AVG, MIN or MAX calculation. Also, the STORE NUM. SAMPLES
feature will report the number of sample readings taken since the instrument was restarted.