I/O Response Time - Omron CJ - 09-2009 Operation Manual

Computing the Cycle Time

10-4-6 I/O Response Time

Basic I/O Units
Minimum I/O Response
Time
Maximum I/O Response
Time
When editing online, the cycle time will be extended by the time that operation
is stopped.
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 Unit's input
turns ON, the data is recognized by the CJ-series CPU Unit, and the user pro-
gram is executed, up to the time for the result to be output to an Output Unit's
output terminals.
The length of the I/O response time depends on the following conditions.
• Timing of Input Bit turning ON.
• Cycle time.
• Type of Rack to which Input and Output Units are mounted (CPU Rack,
CPU Expansion Rack, Expansion Rack).
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 the total of the Input ON delay, the cycle
time, and the Output ON delay.
Note The Input and Output ON delay differs according to the Unit used.
(Interrupt to CPU Unit)
The I/O response time is longest when data is retrieved immediately after I/O
refresh of the Input Unit.
The maximum I/O response time is the total of the Input ON delay, (the cycle
time × 2), and the Output ON delay.
Input
Input ON delay
Cycle time
Instruction
execution
Output
Minimum I/O response time
Section 10-4
I/O refresh
Cycle time
Instruction
execution
Output ON delay
469