Frequently Asked Questions: OMA Process Analyzers

Calibration

How is the analyzer calibrated?

Our analyzers are calibrated by obtaining an absorbance spectrum while flowing a standard mixture of known composition (i.e. "cal gas" or "calibration fluid") through the flow cell. This procedure allows the system to produce absorption coefficients for each measurement wavelength, and thereby 'recognize' the distinct absorbance curve of the calibrated analyte.

What calibration fluid is required?

For gas applications, we typically recommend that you use a calibration gas at 75-80% of the full scale concentration balanced in a nitrogen background.

Please inquire with technical support to determine the ideal calibration fluid for your application.

How often is calibration required?

Re-calibration is not required under normal conditions. The analyzer reading is periodically normalized by Auto-Zero, which resets the absorbance baseline using a zero-absorbance fluid.

Do I need to re-calibrate if...

...I change the flow cell?  Not necessarily. For example, if changing from a 250mm flow cell to a 400mm flow cell, you can simply enter a span factor to adjust for the change in path length.

Maintenance

What preventative maintenance is required?

The optical windows of our analyzers need to be cleaned once per month in typical process conditions. This is a 60-second task.