Network Communication; Device Addressing; Link Active Scheduler - Fisher FIELDVUEDVC6200f Instruction Manual

Instruction Manual
D103412X012
AO Block
D If the valve position is below the low cutoff value, the AO block READBACK status limit is LOW_LIMITED.
D If the valve position is above the high cutoff value, the AO block READBACK status limit is HIGH_LIMITED.
D If the transducer block actual mode is Auto and the above conditions are not true, the AO block READBACK status
limit is NOT_LIMITED.
D If the transducer block actual mode is Out of Service, the AO block READBACK status limit is CONSTANT.
DO Block
D If the transducer block actual mode is Auto, the DO block READBACK_D status is NOT_LIMITED.
D If the transducer block actual mode is Out of Service, the DO block READBACK_D status is CONSTANT.
The control strategy should be configured to monitor the Analog Output block status and take action where
appropriate when the status is no longer Good.

Network Communication

Figure D‐3 illustrates a simple fieldbus network consisting of a single segment.
Figure D‐3. Simple Single‐Link Fieldbus Network
LAS
LINK MASTER
LAS = Link Active Scheduler
B2712‐1

Device Addressing

Fieldbus uses addresses between 0 and 255. Addresses 0 through 15 are typically reserved for group addressing and
for use by the data link layer. If there are two or more devices with the same address, the first device to start will use its
programmed address. Each of the other devices will be given one of four temporary addresses between 248 and 251. If
a temporary address is not available, the device will be unavailable until a temporary address becomes available.
Commission devices use addresses 20-35, and standby devices use addresses 232‐247.
Link Active Scheduler (LAS)
There is only one active Link Active Scheduler (LAS) for the entire fieldbus control system. The digital valve controller
includes an LAS. The Link Active Scheduler operates as the bus arbiter for the link, and
Fieldbus Segment
BASIC DEVICES
DVC6200f Digital Valve Controller
F Fieldbus Communication
OUNDATION
February 2017
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