Filter
Top Products
Reference Manual
00809-0400-4728, Rev AA
June 2011
Rosemount 644
3-4
Capabilities 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.
Block Execution times
Analog Input = 45 ms
PID = 60 ms
FOUNDATION FIELDBUS
FUNCTION BLOCKS
For reference information on the Resource, Sensor Transducer, AI, LCD
Transducer blocks refer to F
OUNDATION 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.
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