7
Toxic (CO)
Value
Run Icon
Composite
Measurement
Screen
CO
2
Value
Toxic and Carbon Dioxide Span Calibration
To perform a span calibration with a specific toxic gas, please reference the toxic gas table. For the
CO
2
span calibration, the range (or span) should be a sizeable fraction of the selected full scale range
of the gas.
NOTE: The range for the CO
2
sensor is 0 to 5,000 ppm. For a span calibration, it is recommended to span
cal to the value you will be measuring (i.e., 2,000 ppm).
1. Connect the appropriate gas, regulator, tubing and cal cap to the EVM.
2. Follow steps 2-4 (in Toxic Zero Calibration section) but select Span softkey in step 3.
(NOTE: For Oxygen span calibration, the typical span is 20.9%.)
Logging Toxic Gases or Carbon Dioxide
1. From the Start screen or any Measurement
screen, press key.
+ To view gas measurements, select either the
Gas or Composite screens (by pressing from
the start screen when Setup is selected.
2. Press key to stop logging. (See “Viewing
logged results” to access past sessions.)
Particulate advanced calibration (Gravimetric filtering)
Gravimetric Calibration Overview
(1)Reset the gravimetric and volume accumulators; (2) Insert a new (sealed) gravimetric cassette;
(3) Measure in the specific location for approximately four to eight hours; (4) Notate the value displayed
in the gravimetric accumulator field (displayed in the particulate screen. (This value is used in
conjunction with the weight of the measured dust in the cassette.); (5) Remove the gravimetric cassette
and weigh the filtered contents. (Typically, sent to a lab for results.); (6) To determine the correction
factor, calculate the ratio between the particulate mass value and the weight from the gravimetric filter
lab analysis.
Measuring particulates
1. From the start screen or any measurement screen, press the key.
(Prior to logging, a 5 second count-down appears.)
2. Press key to end the logged session. (See “Viewing logged results” to view past sessions.)
