Analog inputs – Rockwell Automation 1788-CN2FF ControlNet-to-FOUNDATION Fieldbus H1 Linking Device User Manual User Manual

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1788-6.5.1 - January 1999

4-2

Using the ControlNet-to-FOUNDATION Fieldbus H1 Linking Device

Analog Inputs

This section describes configuration of the linking device to access any
analog value (and status) in a Fieldbus device. It also describes the
attributes of the created ControlNet analog input object.

The linking device contains a number of MAI block instances. Each
instance of the MAI block is the software equivalent of an analog input
module in an I/O subsystem. Each MAI block has eight channels, with each
channel containing a float and a status pair. The linking device assigns a tag
to each MAI block in the form CNetMacId

xx_AI_Modulei-j, where xx is

the ControlNet network address,

i is the Fieldbus channel number, and j is

the module or instance number.

Configuration of Analog Inputs

When the NI-FBUS Configurator is started, and continuously thereafter, it
lists all the devices and the function blocks in each device in its browse
window. This includes the AI function blocks in the Fieldbus devices and
the MAI function blocks in the linking device. You must connect the
Fieldbus AI function blocks that will be accessed by ControlNet controllers
(or devices) to the MAI channels, as shown in Figure 4.1.

Figure 4.1 Sample Single Macrocycle MAI Configuration

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