Omron SYSMAC C500-NC113, Operation Manual

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9-1 Section
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9-1-4 Reading PCU Status
There are two ways to send PCU status to the CPU Unit. The first way is the “I/O
refresh data” method, in which the status is transferred from the Position Control
Unit to the CPU Unit with each I/O refresh. The other way is the “Status Area”
method, in which the Intelligent I/O Read instruction is used to read the detailed
information in the Position Control Unit’s Status Area (15 words for the NC211 or
8 words for the NC113) to the CPU Unit.
IR words
CPU Unit Position Control Unit (NC211)
I/O refresh
I/O refresh data
Word 0
Word 1
Word 2
Word 14
Intelligent I/O
Read instruction
Status area
n+1 n+1
s+0
READ
#0015
n+1
s
9-1-5 Programming Precautions
To write commands or data to the Position Control Unit, use the Intelligent I/O
Write instruction (WRIT). To read the status from the Position Control Unit, use
the Intelligent I/O Read instruction (READ). When using these instructions, be
careful about the following points.
1, 2, 3... 1. The Position Control Unit’s shared memory is not completely freed immedi-
ately following execution of WRIT or READ, so the Position Control Unit will
ignore either of these instructions if they are again executed at that time.
Therefore, do not execute either of these instructions consecutively.
CPU Unit
Position Control Unit
Command or data
Status
Shared
memory
Reading of
command or
data
Writing of
status
WRIT
READ
WRIT
READ
a)
X
WRIT
WRIT
b)
X
READ
READ
c)
X