Rockwell Automation 1395 ControlNet Communication Board - Manual (Page 21)

3–7 Configuration & PLC Interfacing
Publication 1395–5.37– March, 1999
integer whose value corresponds to the allowable values in Drive Units
for parameter 106.
If the data transferred between the Drive and PLC Controller will be
manipulated (in the PLC Controller) in units other than Drive Units,
the PLC Controller program must scale the information. The scaled
information must be based on the Drive Units definitions for the
parameters in the Drive. The External Vel Ref (parameter 154) is in
Drive units where 4096 is defined as base speed. If the PLC Controller
program is written in terms of feet per minute (FPM), then FPM must
be converted to Drive Units before being sent to the Drive.
Figure 3.5 provides an example PLC Controller program which could
be used to control the Drive. Based on the configuration shown in
Figure 3.4 the PLC Controller program will be transferring information
to parameter 150 and 154 in the Drive. Integer file N7 in the PLC is
being used for Drive logic control and integer file N10 word 01 is used
to store the Drive speed reference. To control the logic operation of
the Drive, the PLC program must control the bits in the output image
table which correspond to the desired operation. Because parameter
300 has been linked to parameter 150 (Figure 3.5), and parameter 300
is associated with group 1 in the output image table, the PLC
Controller program will be controlling bits in word 0:20.