EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 187)

Analyzing Traces and Events
OTDR 173
Analyzing the Fiber on a Specific Fiber Span
³
Use one of the double-arrow buttons to move marker A from event
to event; this will designate an existing event as a span event.
Note: Each of the first three elements may lead to the creation of a new event,
except if your location corresponds to an already existing event on the
trace.
4. Press Set Span Event to set the span start or span end marker on the
appropriate event in the trace display.
5. If you want to define the new span start and/or end as the default
values, press Update Span Position. The values will be transferred to
the Acquisition tab of the Setup window. For more information, see
Setting a Default Span Start and Span End on page 83.
Changes to the span start and span end will modify the contents of the
events table. The span start becomes event 1 and its distance reference
becomes 0. Only events between the span start and span end will be
numbered in the trace display and Event table. The cumulative loss is
calculated within the defined fiber span only.
I
MPORTANT
To keep a set fiber span during trace reanalysis, activate the fiber
span delimitation memory (see Saving the Span-Start and Span-End
Information on page 465). Otherwise, the span start and span end
markers are reset to zero in the process.