Yokogawa RotaMASS 3-Series - Manual (Page 165)

APPENdIX 7. LINK MASTEr FUNCTIONS
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IM 01R04B05-00E-E 3rd edition July 30, 2010-00 all Rights Reserved. Copyright © 2005, Rota Yokogawa
APPENdIX 7. LINK MASTEr FUNCTIONS
A7.1 Link Active Scheduler
a link active scheduler (LaS) is a deterministic, centralized bus scheduler that can control communications
on an H1 fieldbus segment. there is only one LaS on an H1 fieldbus segment.
a RotaMaSS supports the following LaS functions.
• Pn transmission: Identifies a fieldbus device newly connected to the same fieldbus segment. Pn is
short for Probe node.
• Pt transmission: Passes a token governing the right to transmit, to a fieldbus device on the same seg-
ment. Pt is short for Pass token.
• CD transmission: Carry out a scheduled transmission to a fieldbus device on the same segment. CD is
short for Compel Data.
• time synchronization: Periodically transmits the time data to all fieldbus devices on the segment and
returns the time data in response to a request from a device.
• Live list equalization: Sends the live list data to link masters on the same segment.
• LaS transfer: transfers the right to be the LaS on the segment to another link master.
A7.2 Link Master
a link master (LM) is any device containing a link active scheduler. 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.
LM
node address:
0x15
Slottime = 5
LM
node address:
0x16
Slottime = 5
node address: 0x10
Slottime = 5
Basic device
node address:
0xF1
Basic device
node address:
0xF2
Basic device
node address:
0xF3
Basic device
node address:
0xF4
LaS
there are 3 LMs on this segment.
LM
Fa0601.EPS
Figure A7-1. Example of Fieldbus configuration-3 LMs on Same Segment