Instruction Execution Times And Number Of Steps; Serial Plc Link Response Time - Omron CJ - 09-2009 Operation Manual

Instruction Execution Times and Number of Steps

10-4-8 Serial PLC Link Response Time

10-5 Instruction Execution Times and Number of Steps

472
The I/O response time between CPU Units (Polling Unit to Polled Unit, or
Polled Unit to Polling Unit) connected in Serial PLC Link (CJ1M CPU Units
only) can be found by means of the formulas provided below. The values will
vary, however, if a PT is connected in the Serial PLC Links, because the
amount of communications data is not fixed.
• Maximum I/O response time (not including hardware delays):
Polling Unit cycle time + Communications cycle time + Polled Unit cycle
time + 4 ms
• Minimum I/O response time (not including hardware delays):
Polled Unit communications time + 1.2 ms
Number of con-
nected Polled Units
Number of discon-
nected Polled Units
Communications
cycle time (Unit: ms)
Polled Unit commu-
nications time (Unit:
ms)
The following table lists the execution times for all instructions that are avail-
able for CJ PLCs.
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
(CJ1H-CPU6@H-R, CJ1H-CPU6@H, CJ1H-CPU4@H, CJ1M-CPU@@ and
CJ1G-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 instruction 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 CJ-series instructions varies from 1 to 15 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 CJ-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 CJ-series instructions, and inaccuracies
The number of Polled Units connected in the Link, within the
maximum number of Units that can be set for the Polling Unit.
The number of Polled Units disconnected from the Link, within
the maximum number of Units that can be set for the Polling
Unit.
Polled Unit communications time × Number of connected
Polled Units + 10 × Number of disconnected Polled Units
When communications speed is "standard":
0.6 + 0.286 × (Number of Polled Units + 1) × Number of Link
words × 2 + 12
When communications speed is "high speed":
0.6 + 0.0955 × (Number of Polled Units + 1) × Number of Link
words × 2 + 12
Section 10-5