GasTech Cannonball3, Reference Manual

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15
2.3.4 Technician mode
Technician mode provides access to all advanced functions
and displays of the Cannonball3.
While in Technician mode the MODE button may be used to
toggle back and forth between the current gas level, peak
readings, STEL/TWA/AVG and information screens.
2.3.4.1 STEL
The STEL (Short Term Exposure Limit) for a particular toxic
gas is the maximum average concentration to which an
unprotected worker may be exposed during any 15 minute
interval. The STEL value displayed by the Cannonball3 is the
average concentration for the most recently completed 15
minutes of operation.
Note: For the first 15 minutes after the Cannonball3 is
initially turned on the STEL reading is a projected value.
The Cannonball3 will begin projecting a STEL value after
the first 30 seconds of operation. For the first 30 seconds
the STEL screen will show an "X" where the reading
should be.
The STEL reading is continuously updated. Audible and
visible alarms will be activated immediately any time the most
recent 15-minute average exceeds the STEL alarm set-point.
Appendix A discusses Permissible Exposure Limit alarm
calculations in greater detail.
2.3.4.2 TWA readings
Time Weighted Average or TWA values are calculated by
taking the sum of exposure to a particular toxic gas in the
current operating session in terms of parts-per-million-hours
and dividing by an eight-hour period.
Note: It is not possible to calculate a toxic gas TWA
reading until the Cannonball3 has been operating for 15
minutes. For the first 15 minutes after start-up, the TWA
screen will show an “X” in place of the calculation. After
15 minutes, the TWA calculation will be shown.
Appendix A discusses Permissible Exposure Limit alarm
calculations in greater detail.
2.3.4.3 Average readings
The average readings displayed by the Cannonball3 are the
simple arithmetic averages registered by the instrument during
the current session of operation.
STEL TWA AVG
CO 0 0 0
H
2
S 0 0 0
O
2
20.9
LEL 0
STEL/TWA/AVG screen in Technician Mode:
2.3.5 Changing operating modes
To change operating modes do the following:
1. Press the MODE button until the information screen is
displayed.
INFORMATION
Date 31 JUL 04
Time of day 14:51
Runtime 10:07
Points logged
100
Temperature 77F 25C
Battery
6.0V
EXIT
MENU
2. Hold down the left arrow key until EXIT appears and is
highlighted (approximately three seconds).
INFORMATION
Date 31 JUL 04
Time of day 14:51
Runtime 10:07
Points logged
100
Temperature 77F 25c
Battery 6.0V
E
E
X
X
I
I
T
T
MENU
3. Press the down navigation arrow once to highlight MENU
and press MODE button to enter the Main Menu.
MAIN MENU
SCREEN CALIBRATION
VIEW ALARMS
DATALOGGER
OPTIONS
ID INFO EXIT
4. Press the up arrow once to highlight OPTIONS and press
the MODE button to enter the Options Menu.
OPTIONS MENU
USER MODE SEC BEEP
PASSCODE LANGUAGE
DECIMAL DILUTION
EXIT
5. Use the navigations arrows to highlight USER MODE and
press the MODE button. The up and down navigation
arrows may then be used to toggle between operating
modes.