Link Master Functions
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.
FVP 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 segment. 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.
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