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Programming Appendix A
Example of Calculating the Cycle Time
An example is given here for FQM1-MMP21 Motion Control Modules connected to a Coordinator Module.
Conditions
Calculation Example for FQM1-MMP21
Online Editing Cycle Time Extension
When online editing is executed from the CX-Programmer while the FQM1 is operating in MONITOR mode to
change the program, the Coordinator Module will momentarily suspend operation while the program is being
changed. The period of time that the cycle time is extended is determined by the following conditions.
• The number of steps that is changed
• Editing operations (insert/delete/overwrite)
• Instructions used
The cycle time extension for online editing will be negligibly affected by the size of largest task program. If the
maximum program size for each task is 5 Ksteps, the online editing cycle time extension will be as shown in the
following table.
When editing online, the cycle time will be extended by the above time.
Note When there is only one task, online editing is processed entirely in the cycle time following the cycle in
which online editing is executed. When there are multiple tasks (cyclic task and interrupt tasks), online
editing is separated, so that for n tasks, processing is executed over n to n
× 2 cycles max.
Item Condition
Motion Control Modules FQM1-MMP21 2 Modules
User program 5 Ksteps LD: 2.5 Ksteps
OUT: 2.5 Ksteps
Peripheral port connection None
Constant cycle time setting None
RS-232C port connection None
RS-422A port connection None
Other peripheral servicing None
Process Calculation Processing time
Without CX-Programmer
connected to peripheral port
1. Overseeing --- 0.029 ms
2. Program execution 40 µs + 0.1 µs × 500 + 0.35 µs × 500 0.265 ms
3. Cycle time calculation (No cycle time set) 0.008 ms
4. I/O refresh 0.048 ms
5. Cyclic refresh 0.021 ms
6. Sync bus Refresh (In Async Mode: 0 ms)
7. Peripheral servicing 0.04 ms
Cycle time 1. + 2. + 3. + 4. + 5. + 7. 0.411 ms
Module Online editing cycle time extension
FQM1-CM001 65 ms max., 14 ms typical
(for a program size of 5 Ksteps)
FQM1-MMP21/MMA21