Cj1-H Functions Arranged By Purpose - Omron CJ1G/H-CPU series Operation Manual

CJ1-H Functions Arranged by Purpose

1-8 CJ1-H Functions Arranged by Purpose
Purpose
Increas- Increasing the speed of both the instruction
ing execution cycle and peripheral servicing.
speed
• Fast large-scale data exchange with the
host is needed even though the PLC pro-
gram is very large.
• Consistently timed data exchange with
SCADA software is needed.
• Faster message communications and con-
trol is needed between distributed PLCs.
• It is necessary to minimize the effects on
the cycle time of future system expansion
or increases in communications.
Maintaining concurrency in the I/O mem-
ory data accessed for instruction execution
and for peripheral servicing (for data larger
than one word).
Not necessarily maintaining concurrency
in the I/O memory data accessed for
instruction execution and for peripheral
servicing (for data larger than one word).
Giving priority to peripheral servicing over
the instruction execution cycle (For example,
to give priority to the read/write response of
CPU Unit data from SCADA software for
process control).
Specifying where index and data registers
are used independently by task for shared
by tasks.
Minimizing cycle time fluctuations and main-
taining consistent I/O response even when
extensive table data and text string data is
being processed.
Improving data link response with a long
cycle time.
Improving DeviceNet remote I/O response.
Improving the response of protocol macro
data transfers for Serial Communications
Units.
Immediately refreshing status data and
other words allocated to CPU Bus Units in
the CIO Area whenever necessary (includ-
ing Ethernet Units, Serial Communications
Units, Controller Link Units, etc.).
Use the Parallel Processing Mode with Synchronous Memory
Access or Parallel Processing Mode with Asynchronous Memory
Access.
Using parallel processing enables the following savings.
For example, if the program consists of basic instructions with a
cycle time of approximately 10 ms and one Ethernet Unit is being
used, the cycle time will be reduced to approximately 90% of the
time for the normal mode. and the peripheral servicing time will be
reduced to approximately 40% of the time for the normal mode.
Use the Parallel Processing Mode with Synchronous Memory
Access.
Use the Parallel Processing Mode with Asynchronous Memory
Access.
The response of peripheral servicing can be adjusted by using the
following modes (listed in order from highest response):
Parallel Processing Mode with Asynchronous Memory Access,
Peripheral Servicing Priority Mode (with a long instruction execu-
tion cycle), Parallel Processing Mode with Synchronous Memory
Access, Normal Mode
Set the program properties from the CX-Programmer to indepen-
dent (default) or shared registers.
Table data processing and text string processing, which often
require time, can be set in the PLC Setup so that they are pro-
cessed in the background. The default is for no background exe-
cution. (For background execution, time slicing is used to
separate processing over several cycles.)
If background execution is used, the effect on the cycle time can
be limited to 4% or less (PLC Setup default setting).
The CPU BUS UNIT I/O REFRESH instruction (DLNK(226)) can
be used at one or more locations in the ladder program. This
enables refreshing data links for specified Controller Link or SYS-
MAC LINK Units, whenever necessary, as well as during the I/O
refresh period. (The actual data that is refreshed depends on the
communications cycle time.)
The CPU BUS UNIT I/O REFRESH instruction (DLNK(226)) can
be used at one or more locations in the ladder program. This
enables refreshing remote I/O for DeviceNet Units, whenever nec-
essary, as well as during the I/O refresh period. (The actual data
that is refreshed depends on the communications cycle time.)
The CPU BUS UNIT I/O REFRESH instruction (DLNK(226)) can
be used at one or more locations in the ladder program. This
enables refreshing data transferred for protocol macros executed
by Serial Communications Units, whenever necessary, as well as
during the I/O refresh period. (The actual data that is refreshed
depends on the communications cycle time.)
The CPU BUS UNIT I/O REFRESH instruction (DLNK(226)) can
be used at one or more locations in the ladder program. This
enables refreshing words allocated to CPU Bus Units in the CIO
Area (25 words) whenever necessary, in the same way that the
IORF instruction is used for other Units.
Section 1-8
Function
65