Spectrex Quasar 900 Open-Path Gas Detection System - Manual (Page 52)

SafEye TM Quasar 900 Gas Detector
40 Zero Calibration
6.6 Zero Calibration
Zero calibration must be done after:
 Installation.
 Realignment.
 Window Cleaning.
 Any change in Detector or Source position.
Precise alignment must be performed prior to the zero calibration procedure.
Zero calibration should be performed in good weather conditions with
insignificant gas concentrations in the surrounding environment or indoors.
➣ To perform the zero calibration procedure:
1 Switch from Normal to Alignment mode indication.
2 Switch from Alignment to Standby mode.
3 Switch from Standby to Zero Calibration mode.
The 0-20mA output should now be at 1mA.
4 Wait up to 60 seconds until it switches to Normal mode. The Detector
reading is now set to normal. The 0-20mA output should now indicate
4mA.
Switching from each position (above first three instructions) can be done
by HOST HART (refer to TM888030) or RS485 (refer to TM888050 or
TM799060), or by moving the magnetic mode selector above the
magnetic switch (see Figure 8).
Figure 8: Magnetic Mode Selector