Sequence Input Instructions - Omron SYSMAC CS Series Operation Manual

Instruction Execution Times and Number of Steps

10-5-1 Sequence Input Instructions

Instruction Mnemonic
LOAD LD
!LD
The total execution time of instructions within one whole user program is the
process time for program execution when calculating the cycle time (See
note.).
Note User programs are allocated tasks that can be executed within cyclic tasks
and interrupt tasks that satisfy interrupt conditions.
Execution times for most instructions differ depending on the CPU Unit used
(CS1@-CPU6@H, CS1@-CPU6@, CS1@-CPU4@H, CS1@-CPU4@) and the
conditions when the instruction is executed. The top line for each instruction in
the following table shows the minimum time required to process the instruc-
tion and the necessary execution conditions, and the bottom line shows the
maximum time and execution conditions required to process the instruction.
The execution time can also vary when the execution condition is OFF.
The following table also lists the length of each instruction in the Length
(steps) column. The number of steps required in the user program area for
each of the CS-series instructions varies from 1 to 7 steps, depending upon
the instruction and the operands used with it. The number of steps in a pro-
gram is not the same as the number of instructions.
Note 1. Program capacity for CS-series PLCs is measured in steps, whereas pro-
gram capacity for previous OMRON PLCs, such as the C-series and CV-
series PLCs, was measured in words. Basically speaking, 1 step is equiv-
alent to 1 word. The amount of memory required for each instruction, how-
ever, is different for some of the CS-series instructions, and inaccuracies
will occur if the capacity of a user program for another PLC is converted for
a CS-series PLC based on the assumption that 1 word is 1 step. Refer to
the information at the end of 10-5 Instruction Execution Times and Number
of Steps for guidelines on converting program capacities from previous
OMRON PLCs.
Most instructions are supported in differentiated form (indicated with ↑, ↓,
@, and %). Specifying differentiation will increase the execution times by
the following amounts.
Symbol
↑ or ↓
@ or %
2. Use the following times as guidelines when instructions are not executed.
CS1-H CPU Units
CPU6@H
Approx. 0.1
Code Length
(steps)
--- 1
--- 2
CS1-H CPU Units
CPU6@H CPU4@H
+0.24 +0.32
+0.24 +0.32
CPU4@H
Approx. 0.2
ON execution time (µs)
CPU6@H CPU4@H
0.02 0.04
+21.14 +21.16
+45.1 +45.1
Section 10-5
CS1 CPU Units
CPU6@
+0.41
+0.29
CS1 CPU Units
CPU6@
Approx. 0.1 to 0.3 Approx. 0.2 to 0.4
CPU6@ CPU4@
0.04 0.08 ---
+21.16 +21.16 Increase for CS
Series
+45.1 +45.1 Increase for
C200H
CPU4@
+0.45
+0.33
CPU4@
Conditions
515