Mitsubishi Electric MELSEC iQ-R User Manual page 30

■Precautions for creating the program
• Each time 5120 logging data points are stored in the flexible high-speed I/O control module, an interrupt program is
executed and the data is transferred to the file register. The approximate instruction processing time of the interrupt
program is obtained by adding up the processing time of instructions accessing the buffer memory areas in the interrupt
program (equivalent to a value of "5.12 times of FROM instruction (1000 points)
+ 1 time of TO instruction (1 point)
time is required, add up the processing time of all instructions used in the interrupt program. For details on the processing
time of each instruction used in the interrupt program, refer to the MELSEC iQ-R Programming Manual (Instructions,
Standard Functions/Function Blocks).
• The approximate processing time of the interrupt program is obtained by adding both the interrupt overhead time and the
refresh processing time (when the refresh processing is set) at the interrupt execution to the instruction processing time of
the interrupt program. The interrupt overhead time and the refresh processing time at the interrupt execution vary
depending on the parameter settings of the CPU module. For details, refer to MELSEC iQ-R CPU Module User's Manual
(Application).
• The following table provides a calculation example for when the interrupt overhead time is 20.6s and the refresh
processing time at the interrupt execution is 0s.
Item
Instruction processing time (as a guide) of
the interrupt program
Processing time (as a guide) of the
interrupt program
• To prevent logging data omission, create the program so that a series of processing of the interrupt program (from the start
to the completion) takes place within 4.02ms
occurs.
*1 This value indicates the maximum processing time of each instruction. ( MELSEC iQ-R Programming Manual (Instructions, Standard
Functions/Function Blocks))
*2 This value is for when the continuous logging is executed every 1s cycle. When using the continuous logging cycle different from 1s,
calculate a reference value (ms) using the following calculation formula.
Reference value (ms) = (Continuous logging cycle (s)  5120 (points))  1000 - 1.1 (ms)
This processing time is a value for the case when the program consists of only the interrupt program which transfers
continuous logging data. If other processing is added to the program, or another program is added, the processing time
becomes longer. Please consider an actual application and configure the system.
1 FUNCTIONS
28
1.3 Continuous Logging Function
*1
") and the processing time of the IRET instruction. If the exact instruction processing
Calculation formula
= (Processing time of the FROM instruction (1000 points))  (5.12 times) + (Processing time of the FROM
instruction (1 point))  (5 times) + (Processing time of the TO instruction (1 point))  (1 time)
+ (Processing time of the IRET instruction)  (1 time)
*1 *1
 5.12 + 4.3s  5 + 2.7s
= 55.6s
= 311.072s
= (Instruction processing time (as a guide) of the interrupt program) + (Interrupt overhead time)
+ (Refresh processing time at the interrupt execution)
= 311.072s + 20.6s + 0s
= 331.672s
*2
after an interrupt factor (storage of 5120 continuous logging data points)
*1
+ 5 times of FROM instruction (1 point)
*1 *1
 1 + 2.2s  1
*1