TPI 777, Manual

Page: 8 / 16

6
ALARM ADJUSTMENT
1. Turn the 777 on by pressing and holding the power button until the display
illuminates.
2. After the warm up period when the main display shows press and hold down the
Zero button for more than 3 seconds until "Ald" is displayed.
3. The alarm level can be adjusted by using the Zero button to cycle through alarm
level 0 to 9. Repeatedly pressing the Zero key will cycle the alarm level number
from 0 to 9 and then back to 0.The alarm levels for each selection are shown below.
4. Once the desired alarm level is selected, press and hold the Zero key for more than
3 seconds until the 777 returns to the main display.
Alarm Levels
ALARM TYPES
The alarm type is adjustable between standard, TWA, and STEL
.
The alarm type is
selected by performing the steps outlined on page 6.
Standard - When the 777 is in the main display mode the CO concentration is shown in
ppm. The alarm will sound at the Alarm Low level as outlined on page 6.
Time Weighted Average (TWA) Alarm - When the 777 is set to this type of alarm the
"TWA" annunciator will be displayed. In this mode the alarm is time weighted and will
sound at the Alarm TWA level as outlined on page 6. A Time Weighted Average (TWA)
is a threshold value based on a 8-hour workday and a 40-hour workweek. For example
the TWA for carbon monoxide is 25 ppm. This means that an average of 25 ppm is
considered to be the safe threshold value for an 8-hour workday.
Short Term Exposure Limit (STEL) Alarm - When the 777 is set to this type of alarm
the "STEL" annunciator will be displayed. In this mode the alarm is based on a 15
minute average and will sound at the Alarm STEL level as outlined on page 6.