Time Weighted Average (Twa) Mode - PerkinElmer Photovac 2020 Manual

2020 Software Manual
Mode on page 62 for details of switching between display modes.

Time Weighted Average (TWA) Mode

The TWA accumulator sums concentrations every second until 8
hours of data have been combined. If this value exceeds the TWA
alarm setting, a TWA alarm is generated. The TWA is not
calculated using a moving average. Once 8 hours of data have been
summed, the accumulation stops. In order to reset the TWA
accumulator, press the "Clr" key.
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 8:00
or 8 hours, 2020 stops accumulating data and the TWA is complete.
TWA calculations are always being performed by 2020. You can
display the results of the calculations by selecting TWA as the
Display mode. See
48