General Operation; Time Weighted Average (Twa) Operation; Overview - Bacharach PGM-IR Operation And Maintenance

CO Monitor
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2.3 General Operation

WARNING: Operate the monitor in its horizontal position (handle facing upwards). Tilting the
monitor to a vertical position while in operation may cause inaccurate measurements to occur.
To turn ON the monitor, lift up the shield located in front of the handle and press the ON/OFF toggle switch. When
the monitor has been powered ON, allow it to warm up for 5 minutes.
If the detected gas level exceeds a preset gas-alarm point, the unit will respond by turning ON the front panel
ALARM (red) light. If the AUDALRM function is activated (page 11), the audible alarm will also turn ON. Pressing
the front panel SILENCE button turns OFF the audible alarm, but the ALARM light will continue to flash as long as
the detected gas level is above the alarm point. The audible alarm will reactivate if the gas-alarm condition is not
cleared within the time period set by the SILENCE function (page 13).
If a system fault occurs (see Fault Code list on page 14), the monitor responds by turning ON the front panel FAULT
(yellow) light. If the AUDALRM function is activated (page 11), the audible alarm will also turn ON. Pressing the
front panel SILENCE button turns OFF the audible alarm, but the FAULT light will continue to flash as long as the
fault is present. The audible alarm will reactivate if the fault condition is not cleared within the time period set by
the SILENCE function (page 11). Both the FAULT light and audible alarm will automatically turn OFF after the cause
of the fault has been eliminated.
A log of the last 30 fault events can be viewed using the monitor's FAULTS function (page 12).

2.4 Time Weighted Average (TWA) Operation

2.4.1 Overview

In addition to displaying the current gas level, the monitor can also calculate and display a Time Weighted Average
ppm value. This value is available in two formats (8 Hour or Continuous). This provides users with the most
appropriate data on their average ppm exposure in the working environment.
TWA operation is selected by using the 2ndUNIT function.
The two TWA formats are identified by the appearance of either "TWA" (for an 8-hour TWA) or 'twa" (for a
continuous TWA) in the upper-right corner of the Data Display screen.
Instruction 3015-9000 Rev 2
MEASURE indicates when the monitor is actively measuring gas. The screen
to the left shows that currently 50 ppm of CO
that a peak measurement of 70 ppm has been made. The operator can
reset the peak value to zero by pressing the ENTER button. The
measurement cycle runs for approximately 4 minutes between purge
cycles. A log of up to 200 previous measurements can be viewed using the
PPM LOG function (page 11).
PURGE indicates when the monitor is resetting its infrared detector to a
baseline of 0 ppm (relative) by using the 386 ppm (absolute) zero-air from
the internal purge bag. The purge cycle runs for approximately 10 seconds.
TWA (upper case letters) is calculated over an 8-hour period. This format is
designed to show the user's average ppm exposure level during a typical
work day. After 8 hours has expired, an asterisk (*) will be displayed but the
TWA will continue to be updated.
twa (lower case letters) is continuously calculated over the operating time
of the monitor. This mode is useful for monitoring an area for a few
minutes or more and is the preferred mode of operation for checking
operating room atmospheres.
Operation
gas is being detected, and
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