Link Master; Transfer Of Las; Example Of Fieldbus Configuration-3 Lms On Same Segment; Backup Of Las - GE FVP110 Maintenance Manual

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Link Master

A link master (LM) is any device containing a link active scheduler (Figure 76). There
must be at least one LM on a segment. When the LAS on a segment has failed, another
LM on the same segment starts working as the LAS.
Figure 76 Example of Fieldbus Configuration-3 LMs on Same Segment

Transfer of LAS

There are two procedures for an LM to become the LAS:
❑
If the LM whose value of [V(ST)V(TN)] is the smallest on a segment, with the
exception of the current LAS, judges that there is no LAS on the segment, such as
when the segment has started up or when the current LAS has failed, the LM
declares itself as the LAS. With this procedure, an LM backs up the LAS as shown
in Figure 77.
❑
The LM whose value of [V(ST)V(TN)] is the smallest on a segment, with the
exception of the current LAS, requests the LAS on the same segment to transfer
the right of being the LAS.
Figure 77 Backup of LAS
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FVP 110 Fieldbus Valve Positioner Manual