User guide

Instruction Execution Times
Appendix C
Memory Usage,
C–4
Example: L20B Fixed I/O Controller
42 XIC and XIO 42 x 1.00 = 42.00
10 OTE instructions 10 x 0.75 = 7.50
10 TON instructions 10 x 1.00 = 10.00
1 CTU instruction 1 x 1.00 = 1.00
1 RES instruction 1 x 1.00 = 1.00
Instruction Usage 61.50
21 rungs 21 x.375 = 7.87
37 data words 37 x.250 = 9.25
User Program Total 78.62
2 I/O data words 2 x 0.75 = 1.50
1 slot 1 x 0.75 = 0.75
Overhead 65.00
I/O Configuration Total 67.25
Estimated total memory usage: 145.87
(round to 146)
1024 – 146 = 878 instruction words remaining
in the processor
Example: 1747-L514 processor, 30-slot configuration, (15) 1746-IA16,
(10) 1746-OA8, (1) 1747-DCM full configuration, (1) 1746-NI4, (1) 1746-NIO4I
50 XIC and XIO 50 x 1.00 = 50.00
15 OTE instructions 15 x 0.75 = 11.25
5 TON instructions 5 x 1.00 = 5.00
3 GRT instructions 3 x 1.50 = 4.50
1 SCL instruction 1 x 1.75 = 1.75
1 TOD instruction 1 x 1.00 = 1.00
3 MOV instructions 3 x 1.50 = 4.50
10 CTU instructions 10 x 1.00 = 10.00
10 RES instructions 10 x 1.00 = 10.00
Instruction Usage 98.00
30 rungs 30 x 0.375 = 11.25
100 data words 100 x 0.25 = 25.00
10 is highest data table file number
10 x 1 = 10.00
4 is highest program file number
4 x 2 = 8.00
User Program Total 163.50
49 I/O data words 49 x 0.75 = 36.75
30 slot 30 x 0.75 = 22.50
Overhead 67.00
I/O Configuration Total 126.25
Estimated total memory usage: 289.75
(round to 290)
4096 – 290 = 3806 instruction words remaining
in processor