6 zero-point calibration – LumaSense Technologies INNOVA 1412i User Manual

Page 153

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Chapter 12

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BE6025-15

1412i Photoacoustic Gas Monitor

LumaSense Technologies A/S

Page 153 of 202

Fig.12.10 Illustration of the calibration data stored in the filter

banks of filters “A” to “E” after a zero-point calibration task

12.6

Zero-point Calibration

To calculate the concentration offset factor for a filter (during a

zero-point calibration) it is necessary to have a humidity gain

factor for the filter, and vice versa. If a humidity gain factor is not

stored in each of the filter banks, which are active during a zero-

point calibration, then it is necessary to perform a combined zero-

point and humidity-interference calibration task. The set-up of this

combined task is discussed in

section 12.11

.

As mentioned in the previous sections, the zero-point calibration task

is not selective. This means that you cannot choose zero-point

calibration of a single filter in the carousel (for example, when a new

optical filter has been installed). When you perform a zero-point

calibration then all the installed filters will be zero-point calibrated.

If it is only a newly-installed optical filter which needs to be

calibrated, then the same procedure used for an individual filter must

be used, see

section 12.5.1

. In this way you can protect your original

concentration offset factors.

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