3 tasks before starting any calibration – LumaSense Technologies 3434i SF6 Leak Detector User Manual
Page 138
Chapter 12
______________________________________________________________________
_____________________________________________________________________________
BE6028-14
3434i SF6 Leak Detector
LumaSense Technologies A/S
Page 138 of 191
Monitor. The signal in the cell is measured with the water vapour
filter and with the installed optical filters.
The water vapour in the cell absorbs light from the water-vapour
filter and from the installed filter, producing signals which are related
to water-vapour’s relative absorption of the light at the wavelengths
transmitted by the optical filter (see
). We know, however,
that the ratio of the signal measured with any one filter (e.g. “A”)
and the signal measured with the water-vapour filter is a constant.
This ratio is related to the Humidity Gain Factor calculated during
the humidity-interference calibration of filter “A”. For example, if the
signal produced by water vapour when using the water-vapour filter,
is 160µV and using Filter “A” is 16µV, then, if the signal measured
with the water-vapour filter is found to be 80µV, we know that this
concentration of water vapour will produce a signal of 8µV when
Filter “A” is used. Measurements made during humidity-interference
calibration of the installed filters therefore enable the Monitor to
compensate any measured signal for water-vapour’s interference.
12.3
Tasks Before Starting Any Calibration
Before starting any kind of calibration task there are several
operations, which need to be performed:
12.3.1 Obtaining a Print-out of Calibration Data in the
Monitor
Whether the Monitor is to be used online or as a stand-alone
instrument, the Calibration Software BZ7002 can be used to check
the Monitor’s existing calibration. Please refer to User manual
BE6034.
Stand-alone Use
With the monitor connected to a printer (details are given in
):
Press PRINT and then S3.
To stop printing, press PRINT again.
12.3.2 Checking the Calibration of Each Installed Optical
Filter
A print-out of the calibration data in the Monitor’s memory is useful
to have for reference. It also enables you to find out how “old”