Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual page 236

CompoBus/S I/O Link Units
Determining the Node Number and Making DIP Switch Settings
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last allocated output word, the CompoBus/S I/O Link Unit is allocated "m+1" as
its input word and "n+1" as its output word.
In the following example, a CompoBus/S I/O Link Unit is connected to a CPU
Unit with 30 I/O points.
Input words
Output words
The input word (m+1) contains the 8 bits of data from the Master Unit and two
CompoBus/S communications flags.
15
Word m+1
0
CompoBus/S Communications Error Flag
0: Normal; 1: Error
CompoBus/S Communication Status Flag
0: Stopped; 1: Communicating
Write the data to be transmitted to the Master Unit in the output word (n+1).
15
Word n+1
0 0 0
The 8 bits of I/O data are not always transmitted simultaneously. In other words,
8 bits of data transmitted from the Master CPU Unit at the same time will not al-
ways reach the Slave CPU Unit simultaneously, and 8 bits of data transmitted
from the Slave CPU Unit at the same time will not always reach the Master CPU
Unit simultaneously.
When the 8 bits of input data must be read together, modify the ladder program in
the CPU Unit receiving the data. For example, read the input data twice in suc-
cession and accept the data only when the two values match.
Unused bits in the CompoBus/S I/O Link Unit's output word can be used as work
bits, but unused bits in the output slaves cannot be used as work bits.
Unused bits in input word cannot be used as work bits.
Node Number
The CompoBus/S I/O Link Unit is a Slave Unit with 8 input bits and 8 output bits.
The node number setting is made using the DIP switch; the inputs and outputs
share the same node number.
The range of possible node number settings is determined by the type of PC the
Master Unit is mounted to and the settings on the Master Unit. For details refer to
the CompoBus/S Operation Manual.
CompoBus/S I/O Link Unit
Word m+1
bits 00 to 07
8 inputs
8 outputs
Word n+1
bits 00 to 07
IR 000
IR 001
CPU Unit with
30 I/O points
IR 010
IR 011
09 08 07
0 0 0 0 0
07
0 0 0 0 0
Data to be transferred to the Master Unit
Section 3-3
IR 002
CompoBus/S
I/O LInk Unit
IR 012
00
Data from the Master Unit
00