HBM FS22 SI, User Manual, Page: 43 / 116

Measuring
FS22 SI
A4249-8.0 HBM: public
43
4.4 Common Measuring Difficulties
There may be the possibility of having measuring mal­
functions due to several problems in the sensing network
or optical connections. A list of some of the usual prob­
lems is described below with the explanation for its
occurrence and correction.
4.4.1 Dirty Connector
When an interrogator is repeatedly being plugged in and
out with optical connectors, it is very important that the
connectors are cleaned prior to any connection. If not,
dust and moisture can be deposited in the interrogator
adaptor and this will compromise measurements. On
Fig. 4.6 a picture of a magnified connector is presented.
The dark gray circle corresponds to the fiber cladding
and the small light gray circle is the core of the fiber. One
picture for a clean connector and one picture for a dusty
connector are presented.
Clean connector
Dirty connector
Fig. 4.6
The most common effect of dirt on the connections is
that there is a large amount of broad band light being
reflected at the connection, at both directions, meaning
that the dynamic range for measuring becomes smaller.