Omron SYSMAC CV Series - Synchronous Operation

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6-2-2 Synchronous Operation
In synchronous operation, instruction execution and I/O refreshing are pro-
cessed along with peripheral servicing (CPU Bus Units, host interface, etc.)
in a single cycle. The cycle time is thus the sum of the time required for
instruction execution and that required for peripheral servicing, and the cycle
time will lengthen as more peripherals are connected.
Instruction Execution Cycle Time
Process Actions Processing time
CV500/CVM1-CPU01-EV2 CV1000/2000/
CVM1-CPU11/21-EV2
Basic
processes
Checks the cycle
time and PC
memory.
Checks the CPU
bus, PC memory,
battery, start input,
and updates the
clock.
Approx. 3.7 ms Approx. 3.5 ms
Event
processing
Execution of non-scheduled requests for
data processing from peripherals.
0 ms if there is no processing request; 20 ms max.
(12% of cycle time is for servicing.)
Program
execution
Program executed. For ladder programs, total execution time for all
instructions varies with program size, the instructions
used, and execution conditions. Refer to
6-4 Instruction
Execution Times for details.
For SFC programs, refer to the CV-series PC Operation
Manual: SFC
.
Timer
refreshing
Updates the PVs of all timers in the
program.
10 µs + 1.1 µs per timer 8 µs + 0.9 µs per timer
Output
refreshing
Output terminals are updated according to
status of output bits in memory (including
Special I/O Units).
8 µs per word (per 16 pts.) 7 µs per word (per 16 pts.)
Input
refreshing
Input bits are updated according to status
of input signals (including Special I/O
Units).
10µs per word (per 16pts.) 8 µs per word (per 16 pts.)
SYSMAC BUS
refreshing
Input bits allocated to Units connected to
Slaves are updated according to status of
input signals.
Output signals sent to Units connected to
Slaves are updated according to status of
output bits in memory.
1 ms per Master plus 60 µs
per word controlled though
each Master
1 ms per Master plus 50 µs
per word controlled though
each Master
CPU Bus Unit
servicing
Starting from Unit #0, events (requests for
non-scheduled data processing) are
processed to refresh BASIC Unit and
Personal Computer Units.
Approx. 1 ms for event processing; approx. 0.8 ms for
BASIC Unit refreshing; and approx. 0.8 ms for Personal
Computer
Peripheral
Device
servicing
If a peripheral device is connected,
commands from it are processed.
1.2 ms
Host interface
servicing (Pin 3
of DIP switch
OFF)
Commands from computers connected
through the host interface are processed.
1.2 ms
NT link
servicing (Pin 3
of DIP switch
ON)
The NT link is serviced when a PT is
connected to the CPU and the NT link is
being used.
Fixed at 2.2 ms
Cycle Time Section 6-2