Rockwell Automation 1771ACN/B_1771ACNR/B,D17716.5.123 U.MNL CONTROLNET ADAPTER - Manual (Page 49)

Appendix
B
Publication 1771-6.5.123 – May 1996
A Practical Example of
ControlNet Concepts
0 1 2 3 4 5 6 7
I/O Chassis Slot Number
PLC-5/40C
0 1 2 3 4 5 6 7
1771-VHSC 1771-VHSC 1771 8 Point In 1771 8 Point In 1771 8 Point Out 1771-P4S
Node 4
Empty Empty
Map
File Size
I:10 1
O:23 2
1771-A2B Chassis set
for 2-slot addressing
This example uses the physical layout and map entry screen for a
simple system as shown above. With this layout:
•
any legal input module in slots 0 and 1 will be read
•
any legal output module in slots 0 to 3 will be properly
controlled
•
you can communicate with nondiscrete modules anywhere in
the chassis
In this example:
•
the input file size is not equal to the output file size
•
the input file location (I:10) is not equal to the output file
location (O:23)
•
the module node address is not related to the input file (I:10)
or the output file (O:23)
•
you can map odd numbered file sizes (I:10 = 1) and file
locations (O:23)
•
you can perform nondiscrete file transfers to slots not mapped
into I/O image space (1771-VHSC in slot 4)
•
the chassis is mapped as slots 0 to 7 regardless of the
addressing mode used (2, 1, or 1/2)
•
all 1771 I/O placement rules for discrete (8, 16 and 32 point)
and nondiscrete modules as defined for addressing modes still
apply (refer to chapter 3).
•
any discrete output modules placed in slots 4 through 7 will
behave as if they are being written all zeroes
•
any discrete input modules placed in slots 2 through 7 will not
be read by the programmable controller
Overview of Example