Placement and Calibration of Sensors
Calibrating Particulates
EVM Series User Manual
44
5.
To insert a sensor, gently push the sensor’s pins into the socket pin of the circuit board so it aligns
accordingly. It will fit securely.
6.
To remove a sensor, pull the senor up horizontally and remove it from the sensor chamber.
7.
When completed, replace the black manifold over the sensors and then place the cover over the
sensor housing. Tighten the screws back into place.
Air inlet cover
Screw 1
Dial-in Impactors
Toxic sensor
Sensor bar-
Remove screw 1 & screw 2
and lift off cover.
Temperature/
Relative Humidity sensor
(Dry bulb thermometer
measures ambient air
temperature)
Screw 2
PID sensor
CO
2
Sensor
Figure 4-2: Sensors’ locations
NOTE:
The Temperature/ Relative Humidity sensor is not user removable.
NOTE:
The user will receive a message on the display when a new sensor is detected or an
existing sensor is no longer detected.
Calibrating Particulates
The EVM is factory calibrated to the “Arizona Road Dust” (also called “ISO Road dust” ISO 12103-1 A2
Fine) standard.
Before you measure particulates, it is recommended to calibrate to the environment you are in. If you
are in an ARD environment, you would adjust the impactor to correlate with a specific particulate setting,
run a calibration based on the particulates in that environment, and compare the results against the
ARD calibration. If you are in any other environment, you would calibrate based on the environment you
are in by determining a correction factor (also called “K-factor”) to the correct variation from the ARD
calibration standard.
