High Alarm Set Point; Stel Alarm Set Point; Twa Alarm Set Point; Stel/Twa Display Option - 3M 740 Serie Instrucciones De Uso

High Alarm Set Point

The High Alarm Set Point for the sensors can be set by pressing the PEAKS/NO button while the High Alarm Set Point is being displayed during warm-up (Fig. 8). To skip
this step, either press the POWER/SELECT button or wait 5 seconds. If a sensor's reading exceeds this set point, it will trigger a High Alarm. To set the alarm levels, use the
arrow buttons to adjust the highlighted digit or the POWER/SELECT button to advance to the next digit. Allowable ranges for the High Alarm Set Point are: Carbon Monoxide
(CO) – 5 to 999 ppm, Hydrogen Sulfide (HS) –  to 00 ppm, Oxygen (OX) – 1% to 5% v/v and Combustible Gas (EX) – 5% to 60% LEL. If the password protection has
been set, you will be required to enter the password in order to change the High Alarm Set Point.
Note: For personal exposures, OSHA considers any environment with oxygen levels above .5% to be oxygen enriched.

STEL Alarm Set Point

The STEL Alarm Set Point for the Carbon Monoxide and Hydrogen Sulfide sensors can be set by pressing the PEAKS/NO button while the STEL Alarm Set Point is being
displayed during warm-up (Fig. 9). To skip this step, either press the POWER/SELECT button or wait 5 seconds. The STEL (Short Term Exposure Limit) is a 15-minute
floating average reading for the Carbon Monoxide and Hydrogen Sulfide sensors. To set the alarm levels, use the arrow buttons to adjust the highlighted digit or the
POWER/SELECT button to advance to the next digit. Allowable ranges for the STEL Alarm Set Points are: CO – 5 to 999 ppm and H
zero will disable the STEL alarm. If the password protection has been set, you will be required to enter the password in order to change the STEL Alarm Set Point.

TWA Alarm Set Point

The TWA Alarm Set Point for the Carbon Monoxide and Hydrogen Sulfide sensors can be set by pressing the PEAKS/NO button while the TWA Alarm Set Point is being
displayed during warm-up (Fig. 10). To skip this step, either press the POWER/SELECT button or wait 5 seconds. The TWA (Time Weighted Average) is an 8-hour floating
average reading for the Carbon Monoxide and Hydrogen Sulfide sensors. To set the alarm levels, use the arrow buttons to adjust the highlighted digit or the POWER/SELECT
button to advance to the next digit. Allowable range for the TWA Alarm Set Point are: CO – 5 to 999 ppm and HS –  to 00 ppm. Setting the value to zero will disable the
TWA alarm. If the password protection has been set, you will be required to enter the password in order to change the TWA Alarm Set Point.

STEL/TWA Display Option

The STEL/TWA Display Option can be set by pressing the PEAKS/NO button while the STEL/TWA Display Option is being displayed during warm-up (Fig. 11). To skip this
step, either press the POWER/SELECT button or wait 5 seconds. Your choices for the STEL/TWA Display Option are to have the STEL and TWA Alarm Display ON or OFF.
If set to ON, the STEL and TWA values are accessible through the PEAKS menu (see Peaks Values section). Change to the desired selection using the arrow buttons and
confirm selection by pressing the POWER/SELECT button. If the password protection has been set, you will be required to enter the password in order to change the STEL/
TWA Display Option.

Latched Alarm Option

The Latched Alarm Option can be set by pressing the PEAKS/NO button while the Latched Alarm Option is being displayed during warm-up (Fig. 1). To skip this step, either
press the POWER/SELECT button or wait 5 seconds. Latched alarms continue to alarm, with peak readings displayed, until the user acknowledges the alarm by pressing
the POWER/SELECT button. Change the Latched Alarm Option to the desired selection and confirm selection by pressing the POWER/SELECT button. If the password
protection has been set, you will be required to enter the password in order to change the Latched Alarm Option.
Fig. 8
High Alarm Set Point
Using a certified gas for a sensor test or calibration with a concentration other than the one listed for this instrument and sensor will produce inaccurate readings. This
means that higher levels of the gas being monitored may be present and could result in overexposure and cause sickness or death . For proper use, see supervisor or
User Instructions, or call M in U.S.A., 1-800--60. In Canada, call Technical Service at 1-800-67-1.

Test Gas Concentration Setting

The Test Gas Concentration Setting can be set by pressing the PEAKS/NO button while the Test Gas Concentration Setting is being
displayed during warm-up (Fig. 1). To skip this step, either press the POWER/SELECT button or wait 5 seconds. This can be changed
to match your test gas if it is not the same concentration as the M Standard Four Gas Mixture Calibration Gas Concentration of 5
ppm CO, 10 ppm H S, 10% LEL (Methane), 18% Oxygen, balance Nitrogen. Use the arrow buttons to adjust the highlighted digit or the

POWER/SELECT button to advance to the next digit. The allowable range for the Test Gas Concentration is: Carbon Monoxide (CO) - 5
to 00 ppm, Hydrogen Sulfide (H S) – 10 to 100 ppm and Combustible Gas (EX) – 10% to 50% LEL. If the password protection has

been set, you will be required to enter the password in order to change the Test Gas Concentration Setting.
Fig. 9
STEL Alarm Set Point
Fig. 10
TWA Alarm Set Point STEL/TWA Display Option
WARNING
9
S –  to 00 ppm. Setting the value to

Fig. 11
Latched Alarm Option

Test Gas Concentration Setting

Fig. 1
Fig. 1