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Ladder Program Execution Appendix B
Ladder Program Execution Time
Example Calculation of Ladder Program Execution Time
Per line 30 µs: Line containing
program
7
µs: Empty lines
*1
Per output CPU Unit output bits (Q) 4
µs*2
Expansion I/O Unit output bits (Y)
Work bits (M)
Holding bits (H)
Timers (T)/Holding timers (#) 15
µs*3
Counters (C)/8-Digit Counters (F) 13
µs
Display bits (D) Hour and minute (CLK)/Year
and month (DAT)/Month and
day (DAT1): 21
µs
Timers (T)/Holding timers
(#)/Counters (C)/Analog
comparators: 28
µs
Characters (CHR)/8-Digit
Counters (F): 38
µs
Weekly timers (@) 4
µs*4
Calendar timers (*) 1
µs
Analog comparators (A) 3
µs
Comparators (P) 7
µs*5
8-Digit Comparators (G) 4
µs
[Q0
[Q1
TT0
[Q2
00
01
02
03
04
I0 I1 I2
Q0
I3
I4
@0 P0 T0
Ladder program execution time =
(30
× 5) + (4 × 3) + 15 + 4 + 7 = 188 (µs)
*5: P0
*4: @0
*3: T0 (output)
*2: Q (outputs) for 3 points
*1: For 5 lines
Z211-E1-03.book Page 131 Friday, November 21, 2008 10:38 AM