Cycle Time And Operations; Cycle Time Example - Omron CPM2C-S100C Operation Manual

Cycle Time
7-1-2

Cycle Time and Operations

Cycle time
1 ms or longer TMHH(––) may be inaccurate when TC 000 through TC 003 or TC 008 through TC 255 are used
(operation will be normal for TC 004 through TC 007).
10 ms or longer TIMH(15) may be inaccurate when TC 004 through TC 255 are used (operation will be normal for TC
000 through TC 003).
20 ms or longer Programming using the 0.02-second Clock Bit (SR 25401) may be inaccurate.
100 ms or longer TIM may be inaccurate. Programming using the 0.1-second Clock Bit (SR 25500) may be inaccurate.
A CYCLE TIME OVER error is generated (SR 25309 will turn ON).
120 ms or longer The FALS 9F monitoring time SV is exceeded. A system error (FALS 9F) is generated, and operation
stops.
200 ms or longer Programming using the 0.2-second Clock Bit (SR 25501) may be inaccurate.
7-1-3

Cycle Time Example

Process
1. Overseeing
2. Wait for completion of CompoBus/S
communications
3. CompoBus/S input refreshing
4. Program execution
5. Cycle time calculation
6. CompoBus/S output refreshing
7. I/O refreshing
8. DeviceNet I/O refreshing
9. Peripheral port servicing
10. RS-232C port servicing
11. DeviceNet communications servicing
Total cycle time
142
The effects of the cycle time on operations are as shown below. When a long
cycle time is affecting operation, either reduce the cycle time or improve
responsiveness with interrupt programs.
In this example, the cycle time is calculated for a Unit. The I/O is configured
as follows:
6 inputs:
4 outputs: 1 word (01000 to 01003)
The rest of the operating conditions are assumed to be as follows:
User's program: 500 instructions (consists of only LD and OUT)
Cycle time:
The average processing time for a single instruction in the user's program is
assumed to be 1.26 µs. The cycle times are as shown in the following table.
Calculation method
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1.26 × 500 (µs)
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(1) + (2) + (3) + - - - + (11) 1.68 ms
Note 1. The CompoBus/S communications wait time can be calculated by sub-
tracting the time required for processes 9, 10, 11, and 1 from the Compo-
Bus/S communications response time.
CompoBus/S wait time = CompoBus/S response time – (9) – (10) – (11) –
(1)
Operation conditions
1 word (00000 to 00005)
Variable (no minimum set)
Time when peripheral
port is used
0.3 ms
0
0.02 ms
0.6 ms
0
0.05 ms
0.06 ms
0.1 ms
0.55 ms
0
0
Section 7-1
Time when peripheral
port is not used
0.3 ms
0.5 ms
0.02 ms
0.6 ms
0
0.05 ms
0.06 ms
0.1 ms
0
0
0
1.63 ms