Справочник Пользователя для National Instruments FP-3000

Chapter 3

Example Applications

3-2

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 National Instruments Corporation

One common application of the FP-3000 is interfacing to a conventional 
device, such as a 4-20 mA pressure sensor or a 4-20 mA temperature 
transmitter. This example helps you configure the FP-3000 to interface to 
a 4-20 mA pressure sensor. This example shows you how to instantiate an 
AI function block, assign a tag to the block, set up scaling parameters and 
range for the I/O channel, schedule the function block, and download the 
configuration to the FP-3000.

Example 1 requires the following materials:

•

4–20 mA sensor, such as a pressure sensor

•

FP-AI-100, FP-AI-110, or FP-AI-111 module (this example assumes 
you are using the FP-AI-110 module)

•

FP-3000 network module

•

Host configuration system capable of instantiating function blocks on 
devices (such as National Instruments NI-FBUS Configurator)

Wire the 4–20 mA current loop into the current source input FP-AI-110 
terminals. For channel zero, use terminals 1 and 17, as indicated on the 
wiring diagram on the front of the FP-AI-110 module. Make sure your 
current loop is powered and the sensor is operating normally.

Configure the software to perform the translation from the 4–20 mA sensor 
signal to the engineering units used on the Fieldbus.

You must create a block for the FP-AI-110 since the pressure sensor is 
connected to a channel on the FP-AI-110 input module. To create a block 
for the FP-AI-110, follow these steps:

1.

Right-click on the FP-3000 entry in your configurator.

2.

Select Instantiate New Block. This causes a dialog box listing all the 
blocks supported by the FP-3000 to appear and allows them to be 
instantiated.