PPM Sentinel 3, Руководство по системе и аксессуарам

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S3x-HB-1-11
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1.4 Care of fibre optic interfaces
Fibre optic links are an excellent alternative to coaxial cable where galvanic isolation is required or long
distances are involved. Due to the nature of fibre however, additional care is required when handling,
installing, and using fibre optic products.
The single-mode fibre optic cable used with Sentinel 3 is terminated with an Angle-Polished Connector
(APC) so correct orientation when making the interface is essential. Particular care should be taken to
avoid confusion between APC (green) and PC (blue) connectors, as they look similar but will not yield the
same performance. It is important to position the alignment key on the cable connector with the matching
slot in the module.
Single-mode fibre is used for the Sentinel 3 system for its high performance characteristics. As this fibre
has a very narrow diameter (9μm) it is far more susceptible to dust contamination than the relatively large
area of a multi-mode fibre. To minimise disruption caused by dirt, the Sentinel 3 fibre optic connectors
incorporate automatic dust protection shutters to help minimise any dust ingress. Despite the use of these
shutters, the optical connectors should be cleaned in accordance with the instructions in this hand book
before each and every connection; even if they have been protected with dust caps.
The protective dust caps on the equipment and cable connectors should only be removed immediately
before the connection is made, and should be replaced immediately after disconnection. When the fibre
optic cables are not connected, it is essential that the cable and equipment connectors are protected by
the dust caps provided with the system. Failure to do so may result in damage to the fibre ends, which
are critical to the system performance.
It is extremely important to ensure mating fibre surfaces are clear of contamination. Small amounts of dirt
and dust on the surface of the fibre can cause significant insertion loss and return loss degradation.
Figure 2: Dirty fibre interface causes performance degradation
Using the correct cleaning product (fluids and swabs) is as important as cleaning the fibre interface itself.
If the wrong fluid is used a residue can be left behind which will then cross-contaminate any clean fibre
surfaces it comes into contact with.
Figure 3: Cleaning fluid residue cross-contaminates clean fibres
Connector performance will be compromised if its end face is scratched or chipped. Failure to clean the
fibre interface can result in permanent fibre damage and signal degradation.