Omron SYSMAC C500-NC113 Operation Manual page 137

9-1-4 Reading PCU Status
CPU Unit
n+1
IR words
s+0
9-1-5 Programming Precautions
1, 2, 3...
CPU Unit
X
a)
WRIT
READ
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.
I/O refresh
Intelligent I/O
Read instruction
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. 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.
Command or data
WRIT
READ
b)
Position Control Unit (NC211)
n+1
READ
#0015
n+1
s
Shared
memory
Status
X
WRIT
WRIT
Section
I/O refresh data
Status area
Word 0
Word 1
Word 2
Word 14
Position Control Unit
Reading of
command or
data
Writing of
status
X
c)
READ
READ
9-1