Rockwell Automation 1747-SCNR ControlNet Scanner Module Reference Manual - Manual (Page 111)

Publication 1747-RM623D-EN-P - June 2006
Application Examples E-33
Words I:3.0 and O:3.0 are reserved. Note that the input data
from the 1746-IA16 module is found in the processor’s input
image word I:3.3, the output data written to the 1746-OB16
module will be from the processor’s output image word O:3.2.
You must also enter a value in the Status Address field. This field
supplies Connection Status information to the processor for each
unique connection. The bit addresses for this field must be even
numbers, because two consecutive bits are used as status for
each connection. The even numbered bit indicates whether the
connection is open or closed and 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.
You have successfully configured a rack connection to the remote
chassis to communicate with the two discrete I/O modules. At this
point, you may also configure the state of the outputs in the remote
ControlNet chassis when the processor is placed into the Program
Mode or if communications is lost to the remote chassis. This is
optional. The default is to turn all outputs off when one of the two
conditions occur. To select other options:
1 . Click the Advanced tab in the Connection Properties window.
IMPORTANT
There is a two 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-ACNR15
chassis will be written to I:3.3 in the SLC processor’s input
image.
The starting input address configured in RSNetWorx for
ControlNet software for this rack connection was I:3.1, but
I:3.1 and I:3.2 are used for status information. Therefore,
the actual input data begins after the two words of status
information. I:3.4 is not used in this example because an
output module resides in slot 2.
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-ACNR15
chassis. In addition, no offset applies to module
connections at all.