A-17
Appendices
NJ-series CPU Unit Software User’s Manual (W501)
A-2 Calculating Guidelines for the Real Processing Times of Tasks
App
A-2-1 Calculating the Average Real Processing Times of Tasks
*1 The values in parentheses are the I/O refresh times when an expansion allocation area is used.
*2 The number of allocated words is the total number of I/O area words that are allocated to all of the slaves.
CPU Bus Units
The following table gives the I/O refresh times for CPU Bus Units. The times are the same regard-
less of whether the Units are used on the CPU Rack or an Expansion Rack.
*1 The following maximum time is added if a protocol macro is executed:
0.1 Number of refresh words [s]
*2 The number of allocated words is the total number of I/O area words that are allocated to all of the slaves.
The user program execution time depends on the specific instructions multiplied by the numbers of
instructions used.
As a guideline, instructions are divided into three groups and the number of instructions in each group
is used for measurements and estimates.
• Standard instructions
• Arithmetic instructions for LREAL data
• Trigonometric instructions for LREAL data
Different instructions are used in a ladder diagram and in ST. Refer to Execution Time for Standard Lad-
der Diagram Instructions on page A-18 and Instruction Configuration for Standard ST Instructions on
page A-19 for information on the instruction configuration.
Simple Estimate
For the number of instructions in each group, read the execution time for each group from the follow-
ing graphs and calculate the total.
• Execution time for standard instructions
• Execution time for arithmetic instructions for LREAL data
• Execution time for trigonometric instructions for LREAL data
This will allow you to estimate the execution time of the user program.
CompoNet Master Unit
CJ1W-CRM21 Communications mode 0 34
Communications mode 1 52
Communications mode 2 88
Communications mode 3 84
Communications mode 8 14 + (1.0 Number of allo-
cated words)
Unit name Model numbers
I/O refresh time per Unit
[s]
Serial Communications Units
CJ1W-SCU42
CJ1W-SCU32
CJ1W-SCU22
2.5
*1
DeviceNet Unit
CJ1W-DRM21 2.5 + 0.1 Number of allo-
cated words
EtherNet/IP Unit CJ1W-EIP21 7.0 + 0.8 Number of tags
User Program Execution Time
Unit name Model numbers
I/O refresh time per Unit
[s]
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