Omron CS1W-LC001 Operation Manual page 126

Description of Operation
Example
3-2-11-2 Minimum external I/O refresh cycle
108
Á 1: Longest operation cycle in the function block group comprising the loop
Á 2: Â is as follows depending on the total number of Field Terminals + CPU
Unit Terminals + Expanded CPU Unit Terminals + Node Terminals +
Send/Receive All Blocks ( Â is incremented by 1 at every 19 Terminals.)
Total number of nodes (Field Terminal + CPU Unit
Terminal + Expanded CPU Unit Terminal + Node
Á 3: Â is the smallest integer satisfying formula 1 below.
Formula 1:
{CY x ( Ã +2) + 20} Ä T – 0.7 < Â
Note 1 +T (operation cycle) is further added when analog values are input and
output at AI/AO Terminals using a combination of Analog Input and Analog
Output Units for all Loop Control Units of version 2.00 or earlier. This value is
not added for Loop Control Units of version 2.50 or later.
Note 2 Calculate CY (cycle time) in 10 ms even if the actual cycle time is less than
10 ms.
Cycle time of 15 ms, max. operation cycle of 0.2 seconds (200 ms), 50
function blocks ( Ã = 3) exchanging data with the CPU Unit, A/D conversion
time = 8 ms, D/A conversion time = 8ms, Analog Input Unit and Analog
Output Units are separate units
 = 0 as (15 x 5 + 20) Ä 200 – 0.7 = -0.225 < Â
Therefore, in this example, the maximum I/O refresh cycle becomes as
follows:
8 ms + (4 x 15 ms) + (3 x 15 ms) + (2 x 200 ms) + (0 x 200 ms) + 20 ms +
8 ms = 541 ms
The minimum external I/O refresh cycle is calculated as follows:
A/D conversion time + (1 x CY) + (
conversion time
where,
CY: Cycle time of the CPU Unit
Max. operation time ( Á 1)
T:
Terminal + Send/Receive All Blocks)
0 to 18
19 to 38
Á
39 to 58
259 to 278
Á
Section
Â
x CY) + (1.6 x T) + (
3-2
Â
1
2
3
14
x T) + D/A