Справочник Пользователя для National Instruments FP-3000
Chapter 1
FP-3000 Network Module Overview
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National Instruments Corporation
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Features of the FP-3000 Network Module
Function Blocks
Conventional devices connected to I/O modules are made visible as
Fieldbus function blocks. Function blocks are software modules which
describe the fundamental elements of an I/O or control system. The
FP-3000, like any FOUNDATION Fieldbus–compliant device, has one or
more function blocks. The function blocks in different devices can be
connected to form a distributed control system.
Fieldbus function blocks. Function blocks are software modules which
describe the fundamental elements of an I/O or control system. The
FP-3000, like any FOUNDATION Fieldbus–compliant device, has one or
more function blocks. The function blocks in different devices can be
connected to form a distributed control system.
The FP-3000 implements FOUNDATION Fieldbus–compliant
I/O function blocks, such as Analog Input (AI), Analog Output (AO),
Discrete Input (DI), and Discrete Output (DO). These blocks provide
functionality such as scaling, trending, and alarming. For example, when
you connect a 4–20 mA pressure transmitter to a FieldPoint I/O, you can
configure an FP-3000 Analog Input function block to convert from
4–20 mA to engineering units. You can set up alarm limits so that the
FP-3000 sends an alarm when the pressure exceeds the limits. The FP-3000
network module can also collect trend samples and broadcast them to
applications on a PC.
I/O function blocks, such as Analog Input (AI), Analog Output (AO),
Discrete Input (DI), and Discrete Output (DO). These blocks provide
functionality such as scaling, trending, and alarming. For example, when
you connect a 4–20 mA pressure transmitter to a FieldPoint I/O, you can
configure an FP-3000 Analog Input function block to convert from
4–20 mA to engineering units. You can set up alarm limits so that the
FP-3000 sends an alarm when the pressure exceeds the limits. The FP-3000
network module can also collect trend samples and broadcast them to
applications on a PC.
PID Control
The FP-3000 implements the FOUNDATION Fieldbus–compliant PID
control function block. This PID can be used to control either an analog
output element connected to FieldPoint I/O or a native Fieldbus device,
such as a valve, connected to the Fieldbus network. The FP-3000 executes
the PID and other function blocks deterministically in accordance to a
configured schedule.
control function block. This PID can be used to control either an analog
output element connected to FieldPoint I/O or a native Fieldbus device,
such as a valve, connected to the Fieldbus network. The FP-3000 executes
the PID and other function blocks deterministically in accordance to a
configured schedule.
Block Instantiation
You can instantiate (create multiple copies of) the PID function block on
an as-needed basis. For example, if you are adding a new loop to an existing
Fieldbus network, you can instantiate a PID function block in the FP-3000
to control the loop. You can also instantiate the I/O function blocks on an
as-needed basis. If you have an 8-channel Analog Input module and you are
using only two channels, you would instantiate two AI function blocks.
You can instantiate additional AI function blocks when you use additional
channels.
an as-needed basis. For example, if you are adding a new loop to an existing
Fieldbus network, you can instantiate a PID function block in the FP-3000
to control the loop. You can also instantiate the I/O function blocks on an
as-needed basis. If you have an 8-channel Analog Input module and you are
using only two channels, you would instantiate two AI function blocks.
You can instantiate additional AI function blocks when you use additional
channels.