Rockwell Automation 1747-ACNR15 ControlNet Adapter Module User Manual - Manual (Page 79)

Publication 1747-UM003A-EN-P
4-51
The Connection Name by default is Discrete 16-Bit Exclusive Owner and this is the
16-bit rack connection you want. The first available I/O addresses are I:3.1
and O:3.1, where the 1747-SCNR is in slot 3 of the processor chassis. The first
available starting I/O addresses have been placed into the Input Address and
Output Address fields, because automatic addressing was previously selected in
the Auto Address Preference screen. Words I:3.0 and O:3.0 are used for status and
control data.
Note that the input data from the 1746-IA16 is found in the processor’s input
image word I:3.3 and the output data written to the 1746-OB16 module is
from the processor’s output image word O:3.2.
The Status Address field must also be filled in. This field supplies Connection
Status information to the processor for each unique connection. The starting
bit address for this field must be an even number because two consecutive bits
are used as status for each connection. The even numbered bit indicates
whether the connection is open or closed. The odd numbered bit indicates
whether the connection is in normal operation or Idle mode. In this example,
the starting address chosen is the first available bit pair, M1:3.600/00.
IMPORTANT
If a rack connection type is changed to a smaller bit
configuration e.g. 32-bit to 16-bit, or 16-bit to 8-bit, the
unused bits for the new connection remains in their
previously programmed states for program mode or lost
communications e.g. last state, safe state, reset off.
NOTE
There is a 2-word offset for input data for rack
connections. Therefore, for this example, the input data for
the input module in slot 1 of the remote 1747-ACN15
chassis is written to I:3.3 in the SLC processor’s input
image.
The starting input address configured in RSNetWorx for
this rack connection was I:3.1, but I:3.1 and I:3.2 are used
for rack slot status information. Therefore, the actual input
data begins after the 2 words of status information. I:3.4
and I:3.5 are not used in this example because an output
module resides in slot 2 and an analog module resides in
slot 3.
Also, note that there is no offset for the outputs in a rack
connection. O:3.2 is the output image word written to the
output module located in slot 2 of the 1747-ACN15
chassis. O:3.1 is not used because an input module resides
in slot 1. In addition, no offset applies to module
connections at all.