Other Warnings; Sampling Methods; Performing A Calibration Verification Test (Bump Test); Sensor Test And Full Test (Calibration) - 3M 740 Serie Instrucciones De Uso

Other Warnings

The warning alarm will cause the red LED to flash and a periodic buzzer to sound when various detector conditions occur. Refer to
the LCD screen to determine the cause of the warning. In most cases, the warning can be silenced by pressing the POWER/SELECT
button. The following conditions may cause a warning alarm:
· Sounds for "FULL DATA MEMORY," silence until next power on.
· Sounds for "LOW BATTERY," silence for 5 minutes (Fig. ).
· Sounds for "SENSOR TEST DUE," silence until next power on.
· Sounds for "REPLACE SENSORS," silence until next power on.
· Sounds for a "FAILED TEST," silence once acknowledged.
· Sounds for "REPLACE SENSOR PACK," requires sensor pack to be replaced.

SAMPLING METHODS

This instrument may be used in diffusion (non-pump) mode or with a separate, external sampling pump. In diffusion mode, the atmosphere being measured reaches the
sensors by diffusing into the sensor openings. Gas detectors in diffusion mode monitor only the atmosphere that immediately surrounds the detector.
This instrument can also be used to sample remote locations with a separate, external sampling pump. During remote sampling, the gas sample is drawn into the sensor
compartment through the probe assembly and a length of tubing. Remote sampling operations allow the atmosphere at the end of the sample probe to be monitored.

PERFORMING A CALIBRATION VERIFICATION TEST (BUMP TEST)

CAUTION
CSA standard C. No.15 states before each day's usage sensitivity must be tested on a known concentration of the currently selected gas equivalent to 5 - 50% LEL
of full scale concentration. Accuracy must be within 0% to +0% of the actual. Accuracy may be corrected by performing a calibration of the unit.
A calibration verification test is the only way to effectively confirm that all characteristics of the detector and the sensors are working correctly.
Ensure that you are in a non-contaminated environment before performing a calibration verification test. To conduct the test, attach the calibration (cal) hood on top of the
sensor inlet. Ensure the calibration gas matches the sensor installed in the instrument. Connect the hose from the gas regulator of the calibration gas bottle to the cal hood.
Turn on the gas.
Compare the displayed values with those of your reference calibration gas source. Apply the calibration gas for a period of at least  -  minutes to ensure sufficient
response time and steady state readings. If the measurement displayed is within ±10% for oxygen or toxic gases and 0% to +0% of applied gas for combustible sensor,
turn off the calibration gas and remove the cal hood. The unit is now ready for use. Otherwise a calibration should be performed.

SENSOR TEST AND FULL TEST (CALIBRATION)

The following steps must be performed when conducting a sensor test or calibration to ensure proper performance of the monitor. Failure to do so may adversely affect
product performance and result in sickness or death.
– Calibrate prior to initial use.
– When performing a sensor test or calibration only use certified calibration gas at the required concentration level. Do not calibrate with expired calibration gas.
– A sensor test should be performed before each use.
– If the instrument cannot be calibrated, do not use until the reason can be determined and corrected.
– Do not cover or obstruct display, audible alarm opening or visual alarm cover.
– Ensure sensor inlet is unobstructed and is free of debris.
– Ensure calibration hood is removed prior to use.
A sensor test should be performed before every use. This is done by checking the detector's response to a known concentration of certified calibration gas. Calibration of
the unit must be performed at least every 0 days or immediately if it does not pass the sensor test. Sensors used beyond the warranty period or exposed to very high
concentrations of gas may require more frequent calibration.
Note: The detector has been calibrated prior to being shipped from the factory. However, to ensure it is performing correctly, a calibration or sensor test must be performed
prior to initial use.

Performing a Sensor Test

M recommends that you perform a sensor test before every use. To carry out a successful sensor test, you need to be in a located in a non-contaminated environment.
You will also need a source of certified calibration gas. A suitable four-gas certified calibration gas mixture available from M is shown in Table . Other test gas
concentrations can be used by changing the test gas concentration at start-up (see Viewing and Changing Settings).
Component
Hydrogen Sulfide
Carbon Monoxide
Methane
Oxygen
Nitrogen
1
CSA standard C. No.15 recommends that the combustible sensor be bump-tested before each day's use with the currently selected gas at a concentration of 5% to 50% LEL. If the indicated concentration is not
within 0% to +0% of the actual concentration applied (e.g. if 5% LEL gas is used an acceptable reading is 5% LEL to 0% LEL), the unit should be calibrated. See testing the sensors and continue application of the
calibration gas until the full test cycle is performed.
Table  – Factory Default Calibration Gas Settings
WARNING
Concentration
10 ppm
5 ppm
0.50% v/v
1
(10% LEL)
18%
Balance
1
Fig. 

Low Battery Warning