Rockwell Automation 1788-FFCT NI-FBUS Configurator User Manual - Manual (Page 12)

Publication 1788-UM052B-EN-P - April 2002
1-4 Fieldbus Overview
Blocks and Parameters
Functions that can be performed by a device are represented as
function blocks. Function blocks contain algorithms and
algorithm-controlling parameters. The 10 standard blocks and
algorithms include the following:
You can change or set the action of a block by changing the settings
of its parameters. Figure 1.3 shows an example of a function block
and its input and output parameters.
Figure 1.3 Function Block Parameters
Function block parameters are classified as follows:
• Input parameters receive data from other blocks.
• Output parameters send data to other blocks.
• Contained parameters do not receive or send data; they are
contained within the block.
Function block parameters are also classified as alarm, trend, or tuning
parameters. These classifications are independent of the input, output,
and contained classifications. For example, an input parameter can
also be an alarm, trend, or tuning parameter.
• Analog Input (AI)
• Analog Output (AO)
• Bias Gain (BG)
• Control Selector (CS)
• Discrete Input (DI) • Discrete Output (DO)
• Proportional Derivative (PD)
• Proportional Integral Derivative (PID)
• Ratio Control (RC)
• Manual Loader (ML)
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