Specifications

Instruction 19-9208 5
N
2
O Monitor 3010
2.5 Time Weighted Average (TWA) Mode
The monitor’s display is toggled between its normal and TWA display
modes by pressing the f1 button.
It is important to know that the time weighted average reading is avail-
able in two formats. This is designed to provide operators with the most
appropriate data on their average ppm N
2
O exposure in the working
environment. The two formats are identified by the appearance of the
letters “TWA” or “twa” in the display. Note that the TWA calculation
gains more significance the longer the monitor is operating. This applies
to both formats.
Note: The TWA/twa format is a factory setting, but it can be
changed by using the optional BACH-COM software.
• TWA (in upper case) is being calculated over a set 8-hour period. This
format is designed to show the user’s average ppm N
2
O exposure level
during a typical work day.
If the monitor is switched OFF and then back ON before 8 hours has
elapsed, then the operator has the option of continuing the current
TWA reading by pressing the f2 button as described in Section 2.3
Start-Up Display. This is intended for instances such as lunch breaks
where the unit is switched OFF for a short time, but the total TWA is
required. Note that during the time the monitor is OFF, the gas
reading will be assumed to be zero and will be added into the TWA if
the previous TWA is continued when the monitor is switched back ON.
• twa (in lower case) is being calculated over a continuous time period.
A new TWA is started by pressing the f1 button as described below.
If the monitor is switched OFF and then back ON, then the operator
has the option of continuing the current TWA reading by pressing the
f2 button as described in Section 2.3 Start-Up Display. Note that
during the time the monitor is OFF, the gas reading will be assumed to
be zero and will be added into the TWA if the previous TWA is contin-
ued when the monitor is switched back ON.