Volatile Organic Compounds VOCs, PID Zero Calibration

Volatile Organic Compounds (VOCs)

VOCs, air pollution with carbon-containing chemicals, are measured using a Photoionization detector 10.6eV. The EVM is equipped to notify you when maintenance and cleaning is required for the PID sensor. A PID sensor error will appear indicating:

(1) if the sensor needs to be cleaned, or (2) the lamp needs replacing.

PID Zero Calibration

The PID ppm zero calibration preferred method is to flush with Zero Grade Air. Alternatively, Nitrogen may be used. For best response time, it is recommended to set the flow rate at 1 LPM. NOTE: Please refer to the EVM series manual for more information on the PID ppm/ ppb sensors.

1.Connect the Zero Grade Air, tubing, and cal. cup to the EVM. (Please skip this step if you are not applying a gas.)

2.Select Calibration from the Start screen and select PID (using up/down arrows).

3.Press Cal softkey and then press Zero softkey. Once level is stabilized, press Set softkey. (Typically takes 60 seconds to stabilize.)

4.Once level has been set, you can press Save or Cancel. (Disconnect components and return to the start screen via On/Off/Esc key.)

PID Span Calibration

Typically, Isobutylene is used when the VOCs are unknown. NOTE: in order to measure

specific VOCs, you will want to use the relevant VOC for your calibrated gas source for a

ppm/ppb sensors. (Please refer to the manual for PID correction factor table; Appendix C for details.)

1.Connect Isobutylene, regulator, tubing and cal cap to the EVM.

2.Follow steps 2-4 above (in PID Zero Cal. section) but select Span softkey instep 3.

Logging VOCs

1. From the start screen or any measurement screen, press key.

•	To view VOCs measurements, select either the Gas or Composite screen by pressing	keys
	from the start screen.

2. Press key to stop logging. (See “Viewing logged results” to access past sessions.)

Run icon

PID sensor measurement

Gas measurement screen