Omron CP1L - 12-2007, Руководство по эксплуатации

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CPU Unit Operation
Section 2-4
2-4-2 I/O Refreshing and Peripheral Servicing
I/O Refreshing
I/O refreshing involves cyclically transferring data with external devices using
preset words in memory. I/O refreshing includes the following:
• Refreshing between I/O words in the CIO Area and CPU Unit built-in I/O,
CP/CPM1A-series Expansion Units, and CP/CPM1A-series Expansion
I/O Units
All I/O refreshing is performed in the same cycle (i.e., time slicing is not used).
I/O refreshing is always performed after program execution.
Peripheral Servicing
Peripheral servicing involves servicing non-scheduled events for external
devices. This includes both events from external devices and service requests
to external devices.
Most peripheral servicing involves FINS commands. The specific amount of
time set in the system is allocated to each type of servicing and executed
every cycle. If all servicing cannot be completed within the allocated time, the
remaining servicing is performed the next cycle.
Note Peripheral USB port, serial port, and communications port servicing is allo-
cated 8% of the previous cycle time by default (the default can be changed)
for each service. If servicing is separated over many cycles, delaying comple-
tion of the servicing, set the same allocated time (same time for all services)
rather than a percentage under execute time settings in the PLC Setup.
2-4-3 I/O Refresh Methods
I/O for CPU Unit built-in I/O and I/O on CP/CPM1A-series Expansion Units
and Expansion I/O Units is performed at the following times.
1,2,3...
1. Cyclic refresh period
2. When instructions with an immediate refresh variation are executed
3. When IORF(097) is executed
Units Max. data exchange Data exchange area
CPU Unit built-in I/O 2 input words
2 output words
I/O Bit Area
CP/CPM1A-series Expansion
Units and Expansion I/O Units Fixed depending on Units I/O Bit Area
Service Description
USB port servicing • Non-scheduled servicing for FINS or Host Link
commands received via a USB port or serial port
from the CX-Programmer, PTs, or host computers
(e.g., requests for program transfers, monitoring,
forced-set/reset operations, or online editing)
• Non-scheduled servicing from the CPU Unit trans-
mitted from a serial port (non-solicited communica-
tions)
Communications port servic-
ing
Communications port servic-
ing • Servicing to execute network communications or
serial communications for the SEND, RECV, CMND
or PMCR instructions using communications ports
0 to 7 (internal logical ports)
• Servicing to execute background execution using
communications ports 0 to 7 (internal logical ports)
Built-in flash memory access
servicing • Read/write processing for built-in flash memory
Memory Cassette access ser-
vicing • Read/write processing for a Memory Cassette