Sensepoint XCD Technical Manual SPXCDHMANEN Issue 15
39
Zeroing and span calibration of Hydrogen Sulfide
sensors
Hydrogen Sulfide sensors can be affected by extreme humidity changes. A sudden increase in ambient
humidity can result in a short-term positive drift in the instrument’s reading. A sudden decrease in
ambient humidity can result in a short-term negative drift in the instrument’s reading. These are most
likely to be noticed during calibration with dry or cylinder gas.
When calibrating Hydrogen Sulfide cartridges, the following should be considered while following the
procedure in 10.1:
1. To zero the sensor, use a compressed air cylinder of 20.9 % v/v oxygen (not Nitrogen). Do not
use background air.
Apply the gas to the sensor for three minutes before using ‘
✓
’ to confirm the zero
calibration.
2. If a span calibration is to be performed, the span calibration gas should be applied to the sensor
immediately after the zeroing procedure. Do not allow the sensor to return to ambient air
conditions between steps 2 and 3.
3.
Apply the span gas for two minutes before using ‘
✓
’ to confirm the span calibration.
To Next Page
Loading...
