Rockwell Automation 1395 ControlNet Communication Board - Manual (Page 18)

3–4 Configuration & PLC Interfacing
Publication 1395–5.37– March, 1999
General The CNA board does not scale or manipulate data that is transferred
between the Drive and PLC Controller. If data in the PLC is
manipulated in units other than Drive units, the data must first be
converted to Drive Units before being sent to the Drive. Consequently,
all scaling of data must be performed in the PLC.
To control Drive parameters the CNA parameters are linked to the
Drive by using source and sink parameters. Refer to the Drive
Installation and Maintenance manual for details on Drive configuration
links.
Discrete PLC Controller Data required by the Drive on a continuously updated basis is
I/O Data Transfer transferred using the I/O image table of the PLC Controller. The data
transfer rate can be determined using the standard conventions for I/O
rack updates of discrete I/O. Refer to the PLC Controller manual for
details.
Refer to Figure 3.2. This figure indicates how data is transferred
between the Drive and PLC controller. The group numbers (0-7) are
used for the transfer of discrete type data. Each group number reserves
a single 16 bit word in both the input and output image table of the
PLC Controller for the rack number assigned. In the Drive these words
are directly linked to internal Drive parameters using source and sink
parameters as shown in Figure 3.3.
Figure 3.2. Full Rack Configuration
Group 0
Groups 0-7 each appear (to the PLC Controller) to
have a 16 bit input and output module installed.
Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7