Application Program Execution
The CPU processes the program from the top (address 0) to the END instruction. The CPU
executes the program left to right and top to bottom. As each rung is evaluated the
appropriate image register or memory location is updated.
The time required to solve the application program depends on the type and number of
instructions used, and the amount of execution overhead.
You can add the execution times for all the instructions in your program to find the total
program execution time. For example, the execution time for a DL240 running the program
shown would be calculated as follows:
Appendix C provides a complete list of instruction execution times for DL205 CPUs.
Program Control Instructions
— the DL240, DL250–1 and DL260 CPUs offer additional
instructions that can change the way the program executes. These instructions include
FOR/NEXT loops, Subroutines, and Interrupt Routines. These instructions can interrupt the
normal program flow and effect the program execution time. Chapter 5 provides detailed
information on how these different types of instructions operate.
DL205 User Manual, 4th Edition, Rev. B
3–34
Chapter 3: CPU Specifications and Operations
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
X0
X1
Y0
OUT
C0
C100
LD
K10
C101
OUT
V2002
C102
LD
K50
C103
OUT
V2006
X5
X10
Y3
OUT
END
STR X0
OR C0
ANDN X1
OUT Y0
STRN C100
LD K10
STRN C101
OUT V2002
STRN C102
LD K50
STRN C103
OUT V2006
STR X5
ANDN X10
OUT Y3
END
TOTAL
1.4µs
1.2µs
1.0µs
7.95µs
1.6µs
62.0µs
1.6µs
21.0µs
1.6µs
62.0µs
1.6µs
21.0µs
1.4µs
1.2µs
7.95µs
16.0µs
210.5µs
Instruction
Time
