Calibration Types: Zero vs. Span

There are two types of calibration; zero and span calibration.

The zero calibration resets the baseline level reading to zero. If the target gas is suspected to be occasionally present, it is best to also use a zero gas cylinder during the zero calibration. If the target gas is not present in the atmosphere, an additional calibration cylinder is not required.

The span calibration is a process that involves first zeroing the baseline reading, then applying a known amount of target gas so that the accuracy and precision of the transmitter can be adjusted to the known value. The known concentration of gas is called a "Span Value" because it represents the span or reach of the calibration curve from zero to that value.

The Sensor Span Value (i.e. Cal Level) in the device menu should be the same as the concentration listed on the calibration gas cylinder.