Allen-Bradley PowerFlex 20-COMM-D, User Manual

Page: 42 / 149

4-4 Configuring the Scanner
Figure 4.4 Edit I/O Parameters Dialog Box
8. Select the type(s) of data exchange (Polled, Change of State, and /or
Cyclic). In our example, we selected Polled.
9. Type the number of bytes that are required for your I/O in the Rx
Size and Tx Size boxes. The size will depend on the following:
• I/O that you enabled in the adapter. This information can be
found in
Parameter 14 - [DPI I/O Active] in the adapter.
• Size of the Reference/Feedback and Datalinks in your drive. This
information can be viewed using
Parameters 07 - [Ref/Fdbk
Size] and 08 - [Datalink Size] in the adapter. A 16-bit word is
two bytes, and a 32-bit word is four bytes.
• The actual size value used in the Rx Size box can be determined
by the setting of the M-S Input parameter as shown in
Table E.A
or Table E.B for “Poll Only.”
• The actual size value used in the Tx Size box can be determined
by the setting of the M-S Output parameter as shown in
Table
E.C or Table E.D for “Poll Only.”
• Table 4.A and Table 4.B show common configuration Tx/Rx
sizes.
In our example, we typed 4 in the Rx Size and Tx Size boxes because
we enabled only the Logic Command/Status for I/O in the adapter
and our drive uses a 16-bit Reference/Feedback.
Both the M-S Input and M-S Output parameters are set to 00001.
Therefore, the Logic Command/Status uses 2 bytes and the
Reference/Feedback uses 2 bytes totaling 4 bytes.