Allen-Bradley PLC-2/30

Timer and Counter Instructions
Chapter 5
523
As an example, we will calculate the execution time for File-to-File move
in the distributed complete mode for the following conditions:
Rate per scan = 256 words operated upon per scan.
File length = 542 words
542 words in file = two full 256 word blocks + 30 words. Therefore, use
2 for the number of blocks operated upon per scan and ignore the +30
words.
Therefore: Time = 85 + 6.8(256) + 14.4(2)
Time = 85 + 1741 + 28.8 = 1855 microseconds
The incremental mode requires an execution time of 62 microseconds.
When false, the File-to-File move and File Complement execution time is
6 microseconds. The first scan the rung is false after the done bit is set
requires 17.6 microseconds to reset flags and counters.
Table 5.F
Average
Execution Times For FiletoFile Move and File Complement
Instructions
Time (Microseconds)
Rate (Words per Scan)
Dist. Complete Mode Complete Mode
5
10
15
25
50
100
256
512
119
153
187
255
425
765
1840
3595
101
135
169
237
407
747
1822
3578
Formulas for more exact approximations can be found in Section 5.6.3.
Incremental mode requires 62 microseconds per scan. When F ALSE, the execution time is 6 microseconds. T o reset flags and
counters requires 17.6 microseconds.
Table 5.G presents average instruction execution times for the logic
instructions File-to-File AND, OR, XOR.
The execution time, T, in microseconds for the distributed complete mode
is given by the equation:
T = 125 + 9.8(Number of words operated upon per scan) + 14.4
(Number of 256 word blocks operated upon per scan)
5.6.4
Logic Instructions
FiletoFile AND, OR, XOR
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