Emerson 644 manual Capabilities, Foundation Fieldbus Function Blocks

Rosemount 644

Reference Manual

00809-0400-4728, Rev AA June 2011

Capabilities

FOUNDATION FIELDBUS FUNCTION BLOCKS

Virtual Communication Relationship (VCRs)

There are a total of 12 VCRs. One is permanent and 11 are fully configurable by the host system. Sixteen link objects are available.

Network Parameter	Value
Slot Time	8
Maximum Response Delay	2
Maximum Inactivity to Claim LAS Delay	32
Minimum Inter DLPDU Delay	8
Time Sync class	4 (1ms)
Maximum Scheduling Overhead	21
Per CLPDU PhL Overhead	4
Maximum Inter-channel Signal Skew	0
Required Number of Post-transmission-gab-ext Units	0
Required Number of Preamble-extension Units	1

Block Execution times

Analog Input = 45 ms

PID = 60 ms

For reference information on the Resource, Sensor Transducer, AI, LCD Transducer blocks refer to FOUNDATION fieldbus Block Information on page A-1.Reference information on the PID block can be found in the Function Block manual document number 00809-0100-4783.

Resource Block (index number 1000)

The Resource Function Block (RB) contains diagnostic, hardware, and electronics information. There are no linkable inputs or outputs to the Resource Block.

Sensor Transducer Block (index number 1100)

The Sensor Transducer Function Block (STB) temperature measurement data includes sensor and terminal temperature. The STB also includes information about sensor type, engineering units, linearization, reranging, damping, temperature compensation, and diagnostics.

LCD Transducer Block (index number 1200)

The LCD Transducer Block is used to configure the LCD meter.

Analog Input Block (index number 1300 and 1400)

The Analog Input Function Block (AI) processes the measurements from the sensor and makes them available to other function blocks. The output value from the AI block is in engineering units and contains a status indicating the quality of the measurement. The AI block is widely used for scaling functionality.

PID Block (index number 1500)

The PID Function Block combines all of the necessary logic to perform proportional/integral/derivative (PID) control. The block supports mode control, signal scaling and limiting, feed forward control, override tracking, alarm limit detection, and signal status propagation.

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