Link Active Scheduler - Emerson Rosemount Reference Manual

Reference Manual
00809-0100-4021, Rev GC
Permitted modes
It is possible to prevent unauthorized changes to the operating mode of a block by configuring
MODE_BLOCK.PERMITTED to allow only the desired operating modes. It is recommended that
OOS always be selected as one of the permitted modes.
Types of modes
For the procedures described in this manual, it is helpful to understand the following modes:
AUTO
The functions performed by the block will execute. If the block has any outputs, these will
continue to update. This is typically the normal operating mode.
Out of service (OOS)
The functions performed by the block will not execute. If the block has any outputs, these will
typically not update and the status of any values passed to downstream blocks will be "BAD". To
make changes to the configuration of the block, change the mode of the block to OOS, and
when the changes are complete, change the mode back to AUTO.
MAN
In this mode, variables that are passed out of the block can be manually set for testing or
override purposes.
Other types of modes
Other types of modes are Cas, RCas, ROut, IMan, and LOW. Some of these may be supported by
different function blocks in the 3144P. For more information, see the Function Block manual
(Document No. 00809-0100-4783).
Note
When an upstream block is set to OOS, it will impact the output status of all downstream blocks.
The figure below depicts the hierarchy of blocks:
Resource block
4.3.4

Link Active Scheduler

The 3144P can be designated to act as the backup Link Active Scheduler (LAS) in the event that
the designated LAS is disconnected from the segment. As the backup LAS, the 3144P takes over
the management of communications until the host is restored.
The host system provides a configuration tool specifically designed to designate a particular
device as a backup LAS. Otherwise, this can be configured manually as follows:
1.
2.
Foundation™ fieldbus configuration
Transducer
block
Access the Management Information Base (MIB) for the 3144P.
To activate the LAS capability, enter 0x02 to the BOOT_OPERAT_FUNCTIONAL_CLASS
object (Index 605). To deactivate, enter 0x01.
Restart the device.
Section 4: F
OUNDATION
Other
Analog Input
function
(AI block)
blocks
fieldbus Configuration
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