Alarm Level Selection. "Air-Free" Co Option Selection - BT CGA-411 Operation Manual

11.

ALARM LEVEL SELECTION. "AIR-FREE" CO OPTION SELECTION

The instrument has an alarm activated at preset levels. Factory set alarm limits are given
in Section 3C. The TRACK GAS scale has both an alarm and a beeper which may be disabled
without disabling the alarm.
To review or change alarm limits, remove the instrument from its carryall and take out
the elongated rubber plug on the side of the instrument. Two push button switches, labeled #1
and #2 in Figure 7, will be exposed. Set the front panel selector switch to AUTO ZERO and
after "Air" is displayed, press switch #2. The pump will stop running and the instrument will
enter a display/set-up mode for alarms and other options.
To Display Alarm Levels Without Changing Them. Each time switch #2 is pressed,
the display advances through the sequence shown in Table 4. The display shows whether an
alarm or other option is ON or OFF, and if ON, at what level.
To Turn Off or On Alarms or Select Options. Alarm levels for gas and CO/H
be adjusted within certain limits or turned OFF, the beeper for the TRACK GAS scale may be
turned OFF, the CO display may be put on an air-free basis, and the block limit for the pump may
be adjusted by using switches #1 and #2. The oxygen alarm limits are always ON at the factory
set levels.
To turn an alarm OFF or select an option, enter the alarm display mode as described
above (set selector switch to AUTO ZERO and press switch #2 once), advance to the relevant
display by pressing switch #2 an appropriate number of times, and then press switch #1. Each
time switch #1 is pressed, the display changes from OFF to ON (and the reverse). If the change
to be made is to turn off a particular alarm or operating mode, once OFF appears on the display,
press switch #2. The display will show a symbol followed by OFF (see Table 4). Exit by turning
the selector switch out of the AUTO ZERO position or continue, by pressing switch #2, to a
subsequent display of another alarm or option to be changed.
The oxygen alarms and the block level for the pump cannot be turned OFF. If OFF is
entered with switch #1, when switch #2 is pressed, the display will show "LoO2" or "HiO2" or
"Pu" followed by a number (19.5 for LoO2, 23.0 for HiO2 and the block limit for the pump).
Fig. 7.
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