Omron CS1W-LC001 Operation Manual page 120

Description of Operation
Example
102
Note 3 The resolution of load rate measurement is 10 ms. (Values less than 10ms
are discarded.)
The readout value resolutions for each operation cycle are as follows:
Operation cycle
0.1 sec.
0.2 sec.
0.5 sec.
1 sec.
2 sec.
For details of the operation execution times for each of the function blocks
and sequence commands in the Step Ladder Program, see Appendix 3 List
of Operation Execution Times. After calculating the total (ms) operation
execution time of each function block based on these tables, take the value
obtained by discarding any value less than 10 ms as the "sum (ms) of
operation execution times of each function block" in the guideline formula.
Function blocks used:
 Function blocks for single control loops:
AI 8-point Terminal (Block Model 584) Ã First-order Lag (Block Model 141)
à Basic PID (Block Model 0110 à AO 8-point Terminal (Block Model 585)
à 1-Block Send Terminal to Computer (Block Model 403) (Basic PID is
sent by CX-Process Monitor)
 Other function blocks:
Step Ladder Program (Block Model 301):
Executed at all times only at STEP00. The ratio of differentiated commands
(DIFD, DIFU) is 5% of all commands as the command type. 50 commands
per Step Ladder Program block are allowed.
Value of load rates according to calculation formula
As the load rates are as follows AI 8-Point Terminals: 0.51 ms, First-order
Lag: 0.46 ms, Basic PID: 1.61 ms, AO 8-point Terminals: 1.44 ms, and 1-
Block Send Terminal to Computer: 2.12 ms, the sum of operation execution
times of each function block becomes 6.14 ms. For this reason, the load rate
becomes 6.14 x n (ms) for a number of loops n.
When all operation cycles are one second, and the number of loops is four,
the sum of operation execution times of each function block becomes 6.14 x
4 = 24.56 ms. As the measurement resolution is 10 ms (values less than
10ms are discarded), the sum becomes 20 ms.
Therefore, the load rate becomes:
20 ms Ä 1000 x 100 + 1% = 2 + 1 = 3%
Readout resolution
10%
5%
2%
1%
1%
Section 3-2