I/O Response Time - Omron CP1H CPU Operation Manual

Computing the Cycle Time
2-7-7

I/O Response Time

Minimum I/O
Response Time
Maximum I/O Response
Time
98
The cycle time extension for online editing is negligibly affected by the size of
task programs. If the maximum program size for a task is 20 Ksteps, the
online editing cycle time extension will be as follows:
CPU Unit
CP1H CPU Unit
When editing online, the cycle time will be extended by according to the edit-
ing that is performed. Be sure that the additional time will not adversely affect
system operation.
Note When there is one task, online editing is processed all in the cycle time follow-
ing the cycle in which online editing is executed (written). When there are mul-
tiple tasks (cyclic tasks and interrupt tasks), online editing is separated, so
that for n tasks, processing is executed over n to n ×2 cycles max.
The I/O response time is the time it takes from when an input turns ON, the
data is recognized by the CPU Unit, and the user program is executed, up to
the time for the result to be output to an output terminal. The length of the I/O
response time depends on the following conditions.
• Timing of Input Bit turning ON.
• Cycle time.
The I/O response time is shortest when data is retrieved immediately before I/
O refresh of the CPU Unit. The minimum I/O response time is calculated as
follows:
Minimum I/O response time = Input ON delay + Cycle time + Output ON delay
Note The input and output ON delays depend on the type of terminals used on the
CPU Unit or the model number of the Unit being used.
Input
(Interrupt to
CPU Unit)
Output
The I/O response time is longest when data is retrieved immediately after I/O
refresh period of the CPU Unit. The maximum I/O response time is calculated
as follows:
Maximum I/O response time = Input ON delay + (Cycle time × 2) + Output ON
delay
Increase in cycle time for online editing
Maximum: 26 ms, Normal: 14 ms
(for a program size of 20 Ksteps)
Input ON delay
Cycle time Cycle time
Instruction Instruction
execution execution
Output ON delay
Minimum I/O
response time
Section 2-7
I/O refresh
Instruction
execution