Rockwell Automation PLC-5 Fieldbus Solutions for Integrated Architecture User Manual - Manual (Page 166)

Publication 1757-UM006A-EN-P - May 2002
7-6 Using the 1788-CN2FF, ControlNet-to-FOUNDATION Fieldbus H1 Linking Device
blocks. The linking device assigns a tag to each MAO block in the
form CNetMacIdxx_AO_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 Outputs
The NI-FBUS Configurator lists all the devices and the function blocks
in each device in its browse window. This includes the AO function
blocks in the Fieldbus devices and the MAO function blocks in the
linking device. You must connect the Fieldbus AO function blocks
that will be controlled by the ControlNet controllers (or devices) to the
MAO channels.
The controller provides the necessary mode handshake for cascade
initialization of the AO block. In this case, you must connect
CN_OUT_Ax of the MAO block to CAS_IN of the AO block, and
BKCAL_OUT of the AO block to BKCAL_IN_Ax of the MAO block, as
shown in Figure 7.4. Note that there is a strict ordering relationship
between CN_OUT_Ax and CN_BKCAL_IN_Ax parameters of the MAO
block. That is, CN_BKCAL_IN_A0 is associated with CN_OUT_A0,
CN_BKCAL_IN_A1 with CN_OUT_A1, and so on.
Figure 7.4 Sample Cascaded AO Configuration
The linking device consumes analog values produced by the
controller on ControlNet and publishes these values on Fieldbus. The
NI-FBUS Configurator sets up the analog output devices to subscribe
to their data on Fieldbus. Each MAO block has its own schedule to
consume data on ControlNet and publish it on Fieldbus. For different
rates of publishing on Fieldbus, you must choose different MAO
blocks as shown in Figure 7.5.