Emerson 644 Link Active Scheduler Block Installation, Resource Transducer Analog Input Other

Reference Manual

00809-0400-4728, Rev AA June 2011

Rosemount 644

NOTE

When an upstream block is set to OOS, this will impact the output status of all downstream blocks. The figure below depicts the hierarchy of blocks:

Link Active Scheduler

Block Installation

Resource	Transducer	Analog Input	Other
Block	Block	(AI Block)	Function
			Blocks

The 644 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 644 will take over the management of communications until the host is restored.

The host system may provide a configuration tool specifically designed to designate a particular device as a backup LAS. Otherwise, this can be configured manually as follows:

1. Access the Management Information Base (MIB) for the 644. To activate the LAS capability, write 0x02 to the BOOT_OPERAT_FUNCTIONAL_CLASS object (Index 605). To deactivate, write 0x01.

2.Restart the device.

Rosemount devices are pre-configured with function blocks at the factory, the default permanent configuration for the 644 is listed below. The 644 can have up to ten additional instantiated function blocks.

•2 Analog Input Blocks (tag names AI 1300, AI 1400)

•1 Proportional/Integral/Derivative Block (tag name PID 1500)

The 644 supports the use of Function Block Instantiation. When a device supports block instantiation, the number of blocks and block types can be defined to match specific application needs.The number of blocks that can be instantiated is only limited by the amount of memory within the device and the block types that are supported by the device. Instantiation does not apply to standard device blocks like the Resource, Sensor Transducer, LCD Transducer, and Advanced Diagnostics Blocks.

By reading the parameter “FREE_SPACE” in the Resource block you can determine how many blocks you can instantiate. Each block that you instantiate takes up 4.5% of the “FREE_SPACE.”

Block instantiation is done by the host control system or configuration tool, but not all hosts are required to implement this functionality. Please refer to your specific host or configuration tool manual for more information.

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