Omron CP1L-EL20DR-D Operation Manual page 585

CompoBus/S I/O Link Units
Note
I/O Allocation
I/O words are allocated to the CompoBus/S I/O Link Unit in the same way as
to other Expansion Units and Expansion I/O Units, i.e., the next available
input and output words are allocated. As shown below, when "m" is the last
allocated input word and "n" is the 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.
CompoBus/S I/O Link Unit
Word m+1
8 inputs
8 outputs
Word n+1
In the following example, a CompoBus/S I/O Link Unit is connected as the first
Unit after the CP1L-EM CPU Unit with 40 I/O points.
CP1L-EM CPU Unit
with 40 I/O points
Input words CIO 0
CIO 1
Output words
CIO 100
CIO 101
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
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
(1) 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 always reach the Slave CPU Unit simultaneously, and 8 bits
of data transmitted from the Slave CPU Unit at the same time will not al-
ways 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 succession and accept the data only when the two values
match.
CompoBus/S
I/O Link Unit
CIO 2
CIO 102
09 08 07
Data from the Master Unit
07
Data to be transferred to the Master Unit
Section 9-6
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