User's Manual

8
SECTION 4 – OPERATING INSTRUCTIONS
4.1 Routine Sensor Calibrations
Calibration is the most important function for ensuring correct operation of the ECO-A-X. The
CAL MODE (flow chart shown in Figure 4-2) is designed to make calibration quick, easy and error
free. A successful ZERO and SPAN calibration requires only four keystrokes. The 4-20mA
output indicates CAL MODE by transmitting 3mA. It then transmits 4mA during the subsequent
CAL PURGE delay to prevent external alarms during calibration. CAL MODE automatically exits if
no keystrokes are detected after 5 minutes.
Follow these calibration guidelines below and also see calibration steps on next page.
• Calibration accuracy is only as good as the calibration gas accuracy. Do not use a gas
cylinder beyond its expiration date.
• Calibrate a new sensor before use.
• Allow the sensor to stabilize before starting calibration (approximately 5 minutes).
• Calibrate on a regular schedule. (Net Safety Monitoring recommends once every 3
months, depending on use and sensor exposure to poisons and contaminants.)
• Calibrate only in a clean atmosphere, which is free of background gas (contaminants).
Figure 4-1: Calibration Gas Input
ECO-A-X