INFICON 2020ppbPRO Portable Photoionization Detector - Manual (Page 55)

ISP-074-576-P1D 49
PEAK Mode
The PEAK mode displays the current detected concentration. The reading is
updated once a second. In the background, the 2020ppbPRO datalogger is
sampling the concentration and measuring minimum, maximum, and average
concentrations for the selected averaging interval. At the end of every interval, one
entry is placed in the datalogger until the datalogger is full.
In order to reset the PEAK reading, press the “Clear” key then select “PEAK” using
the “Down Arrow” key then press “Clear”.
Datalogger
Interval Operation
The microprocessor accumulates all readings in an averaging interval that you
select, and determines the minimum, average and maximum readings. It stores
these numbers along with the highest priority instrument status and the most recent
time and date.
These recorded data can now be reviewed and edited. Recorded data can also be
printed using the PC. For each averaging interval, the 2020ppbPRO prints the
minimum of all the minima, the average of all the readings for the interval and the
maximum of all the maxima.
In PEAK mode, the reading is updated once a second. In the background, the
2020ppbPRO datalogger is sampling the concentration and measuring min, max,
and average concentrations for the selected averaging interval. At the end of every
interval, one entry is placed in the datalogger until the datalogger is full.
In STEL mode, 15 samples are combined to form a 15-minute average. Once every
minute, the oldest of the 15 samples is replaced with a new one-minute average.
This moving average provides a 15-minute average with a one-minute update rate
so the meter display will only update once every minute. STEL is set to zero each
time the instrument is turned on.
STEL calculations are always being performed by the 2020ppbPRO. You can
display the results of the calculations by selecting STEL as the Display mode.
TWA mode sums concentrations every second until 8 hours of data have been
accumulated. Once 8 hours of data have been summed, the accumulation stops.
This sum will only be complete after 8 hours, so the meter displays the current sum
divided by 8 hours. While you are in TWA mode, the time on the status display will
show the number of minutes and hours of data that TWA has accumulated. When
this reaches 8 hours, the 2020ppbPRO stops accumulating data and the TWA is
complete.
TWA calculations are always being performed by the 2020ppbPRO. You can display
the results of the calculations by selecting TWA as the Display mode.
Interval mode logs readings at user-selected intervals of 1 second to 999 seconds.