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3.5 Print Mode (Reset):
3.5.1 Print:
From the display with four dashes, pressing the PRINT key enters the
PRINT mode. The display will show "PrLL" or "SEr" based upon which
cable, parallel or serial, is plugged into the unit. With "SEr" in the display,
the unit will accept commands from a personal computer or QuestSuite™
for Windows software. Serial communications are at a fixed rate of 9600
baud. Pressing the enter key initiates printing.
3.5.2 Reset:
To reset the unit while in the PRINT mode, press the ▼ arrow key. The
display shows "rSt" which allows resetting of the logged memory. Press and
hold the enter key for a three second countdown to reset the logging
memory. This will clear all recorded sessions but will not affect any user
setup options. After a complete reset, the unit automatically returns to the
display with four dashes.
3.6 Run Mode:
While four dashes are shown in the display, the unit automatically enters the
RUN mode after thirty seconds or after pressing the enter key. The display
will show the current gas level along with the RUN and LVL annunciators.
In the RUN mode, pressing the arrow keys will display the following items:
Level, STEL (Toxic), TWA (Toxic), Peak Level, LO Level (oxygen), Peak
STEL (Toxic), Average Level, Time, Temperature, and the chemical
symbol corresponding to the installed sensor. Press the enter key to turn on
the backlight without changing the item in the display.
Close the run mode by pressing and holding the on/off key while a three
second close (CLS) countdown is shown in the display. This closes the
session. The next time the unit enters the run mode, it begins a new session.
3.7 Zeroing:
THE SENSOR'S SENSITIVITY CHANGES OVER TIME AND AFTER
USE, SO TO ADJUST FOR THIS, PERFORM THIS EXERCISE PRIOR
TO EVERY USE.
Note:
Fresh, uncontaminated air is necessary for this procedure. (Perform
away from heavy traffic, excessive cigarette smoke, etc.) If such an
atmosphere is difficult to reach, zero air cylinders are available.
Zeroing the sensor adjusts for small baseline drifts which occur over time in
electrochemical sensors.
Zero the unit by pressing the zero key from the display with four dashes or
as one of the options available through the setup mode. The LVL and
ZERO annunciators appear along with the current gas level. The gas level
displayed should be stable before continuing. Press the enter key to zero the
unit. If successfully zeroed, the display will show the current gas level as
zero (except in the case of oxygen where the display will *show 20.9). An
unsuccessful zero results in an error message appearing in the display.
If the level reading is high prior to attempting to initiate a zero, an error
occurs. Typical causes include: the presence of gas, the sensor has recently
been put in the unit and has not had enough time to settle, or the sensor is
old and can no longer be adjusted. Make certain that the environment is
free from toxic gases and the sensor has been under power long enough to
have settled. If the unit still can not successfully perform a zero, replace the
sensor.
3.8 Calibration:
Note:
You must zero your unit prior to calibration. Perform this operation in
a non-hazardous area. (See Section 3.7 "Zeroing" on page 13).
First check the calibration level. While in the SETUP mode, use the arrow
keys to move through the menu until the CAL and LVL annunciator
appears. Check the calibration level shown on the display against the level
printed on the calibration gas cylinder. If they differ, change the calibration
level in the unit to match the calibration gas. (See Section 3.3.2 "Calibration
Level" on page 11).
Snap the unit's calibration cup over the top of the unit so that the cup
chamber is over the sensor. See Figure 2. Calibration on page 15.
Check the Minimum Flow Rate Table (Section 3.8.1 on page 16) for the
specific gas to be sure the regulator is adequate. Tightly screw the regulator
onto the calibration gas cylinder and check the hose's connection to the
regulator to be sure it is secure. Firmly place the end of the hose onto the
nozzle of the unit's calibration cup.
Turn the knob on the regulator counter-clockwise as far as it will turn to
release the gas.
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