Rockwell Automation 20-COMM-ER 20-COMM-ER Dual-Port EtherNet/IP Communication Adapter User Manual - Manual (Page 97)

Rockwell Automation Publication 20COMM-UM015B-EN-P - July 2013 97
Using the I/O Chapter 5
Understanding Controller Data Table Addresses
Because MicroLogix 1100/1400 controllers are 16-bit platforms and are used
with the 32-bit 20-COMM-ER adapter, the data will be transposed from the
least-significant word (LSW) to the most-significant word (MSW) in the
controller.
When the I/O was configured ( Chapter 4 ), an available data table address (N20)
was used. Figure 29 shows the entire data file address structure for this example.
Figure 29 - Data File Table for Example Ladder Logic Program
Important: The N20:0 data table address in this example is used to set a
control timeout value (in seconds) which determines how long
it will take the adapter to detect a communication loss. Enter a
valid value (1…32767) for N20:0. A value of zero (0) is not
valid, because it disables the timeout and all I/O connections
(Logic Command/Status, Reference/Feedback, and Datalinks)
intended for the drive will not execute. A timeout value of
5…20 seconds is recommended.
Depending on the drive you are using, Table 11 , Table 12 , Table 13 , or Table 14
show the I/O definitions as they relate to the N20 data table ( Figure 29 ) being
used in this example.
When using PowerFlex 70 or 70 EC, PowerFlex 700, PowerFlex 700VC drives, or
SMC Flex controllers—which all contain INT (16-bit format) data types, you
will read from and write to the MSW data table address in the controller.
When using PowerFlex 700 VC drives or SMC-50 controllers, which contain
DINT (32-bit format) data types, you will read from and write to the LSW data
table address in the controller.
When using PowerFlex 700S drives, which contain both DINT (32-bit format)
and REAL (floating point format) data types, you will always read from and write
to the LSW data table address in the controller first. Then if the data value
exceeds 16 bits, the remaining value will be in the MSW data table address.