YOKOGAWA F3LR02-0N, User Manual

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B5-2
IM 34M06H45-01E 7th Edition : Aug.30, 2019-00
B5.2 Example of I/O Refresh Time Calculation
This example calculates the I/O refresh time for the following system configuration.
FB0521.VSD
Subunit 1
(Substation 1)
F3LR02-0N
150m
500m
Subunit 2
(Substation 2)
Main unit
(Master station)
Power
supply
module
Power
supply
module
Power
supply
module
Input: 32-point module x 2
Output: 32-point module x 1
Input: 32-point module x 3
Output: 32-point module x 2
Figure B5.1 An Example of I/O Refresh Time Calculation (for F3SP22/28/38/53/58/59/66/67)
Step 1
Calculate the ‘time dependant on transmission distance’
1.0µs x
(150 +500) (m)
100 (m)
= 6.5µs
-
Step 2
Calculate the ‘number of modules, converted to 16-point basis’
- Read Input = 32 points × 5
→
2×5 = 10
- Write Output = 32 points × 3
→
2×3 = 6
Step 3 Calculate the total time
Read input access = (9µs + 6.5µs) x 10 = 155µs
Write output access = (15µs + 6.5µs) x 6 = 129µs
I/O Refresh Time = 284µs
(+