Flowserve 3400IQ Digital Positioner - Manual (Page 42)

Logix 3400IQ Digital Positioner FCD LGENIM3402-00 – 0/07
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Device Objects
Link objects allow the transfer of process data from one block to another. View, Alert and Trend
objects handle function block parameters for operator interface of views, alarms and events, and
historical data. A brief description of these objects is presented in the following sections.
8.3 Block Description
Block Objects
Blocks are elements that make up the FBAP. The blocks contain data (block objects and parameters)
that define the application, such as the inputs and outputs, signal processing and connections to
other applications. The Logix 3400IQ digital positioner application contains the following block
objects:
Resource block
Transducer block
Analog Output (AO) function block
Proportional Integral Derivative (PID) controller function block
Table 8.1 briefly describes the operation of these blocks.
Table 8.1 Function Block Application Process Elements
Block Type Function
Resource Contains data which describes the hardware (physical) characteristics of
the device. The resource block does not perform any action, but contains
parameters that support application downloads.
Transducer Isolates the function blocks from I/O devices such as sensors, actuators
and switches. The transducer block interfaces with the hardware to
produce an output. It also contains device-specific parameters, such as
calibration and diagnostics parameters.
Analog Output (AO) function block Performs basic automation functions that are integral to automated
control and processing operations. The AO block performs functions like
engineering units scaling, output scaling, alarming, and back calculation,
when connected as a cascade to a PID or other block
PID Controller function block Performs standard or robust proportional integral derivative algorithm
used in closed-loop processing.
FBAP Block Diagram
Figure 8.1 shows the important elements of the Logix 3400IQ digital positioner FBAP. Many param-
eters are omitted for clarity.
Figure 8.1 FBAP Block Diagram Example
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•
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Resource
Block
PID Block
IN OUT
BKCAL_IN
Resource
Communication Stack
Algorithm
AO Block
Scaling
CAS_IN
BKCAL_OUT
OUT
Transducer
Block
channel
Value
read/write read/write read/write read/write
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Positioner
Circuitry