Omron SYSMAC C2000H Operation Manual page 235

Cycle Time
Overseeing
Output refreshing and
Unit servicing
I/O bus check
Output refreshing
Remote I/O
servicing
Peripheral device
servicing
Host Link Unit
servicing
PC Link Unit
servicing I and II
Program execution
Input refreshing
230
the time that is required for the CPU to complete one of these cycles. This
cycle includes basically four types of operation.
1. Overseeing
2. Output refreshing and Unit servicing
3. Input refreshing
4. Program execution
The cycle time is the total time required for the PC to perform all of the above
operations. Of these, number two, output refreshing and Unit servicing, and
number four, program execution, are executed in parallel. Because Unit serv-
icing is repeated until program execution is completed (see below), output
refreshing and Unit servicing time will be the same or longer than the pro-
gram execution time. The cycle time will thus be the total of the time required
for overseeing operations, the time required for output refreshing and Unit
servicing, and the time required for input refreshing.
Cycle time = overseeing time + output refreshing and
Unit servicing time + input refreshing time
The second of the above four operations is composed of up to six separate
components. The breakdown of this operation and the function and time re-
quired for each operation are shown in the following table.
Approx. 3.0 ms + sync time (1.0 ms)
0.8 ms
µ
18 s per output word
µ
1 ms per Master plus 20
controlled though each Master
1.5 ms per service if Unit is mounted;
0.5 ms if Unit is not mounted.
1.5 ms per service if Unit is mounted;
0.5 ms if Unit is not mounted.
1.5 ms per service if Unit is mounted;
0.5 ms if Unit is not mounted.
Total execution time for all instructions
varies with program size, the instruc-
tions used, and execution conditions.
Refer to 6-3 Instruction Execution
Times for details.
µ
25 s per input word
All Link Units and peripheral devices are serviced once each cycle in the or-
der given in the above table. If more time is required for program execution
Watchdog timer set and cycle time
checked. CPUs synchronized for
C2000H Duplex System.
I/O connections and bus operation
checked.
Output signals sent according to
status of output bits in memory.
Inputs and Outputs in Remote I/O
s per word
Systems refreshed, i.e., output signals
sent according to output bit status and
input bits set according to input signal
status.
Commands from Programming De-
vices and Interface Units processed.
Commands from computers con-
nected through Host Link Units proc-
essed.
Data communications for PC Link
System processed.
Program executed.
Input bits set according to status of
input signals.
Section 6-1