Automationdirect.com DirectLOGIC DL205 Series User Manual page 125

Chapter 3: CPU Specifications and Operations
Application Program Execution
1
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.
2
The time required to solve the application program depends on the type and number of
instructions used, and the amount of execution overhead.
3
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
4
shown would be calculated as follows:
5
Instruction
6
STR X0
OR C0
ANDN X1
7
OUT Y0
STRN C100
8
LD K10
STRN C101
OUT V2002
9
STRN C102
LD K50
STRN C103
10
OUT V2006
STR X5
11
ANDN X10
OUT Y3
END
12
TOTAL
13
14
Appendix C provides a complete list of instruction execution times for DL205 CPUs.
A
Program Control Instructions — the DL240, DL250–1 and DL260 CPUs offer additional
instructions that can change the way the program executes. These instructions include
B
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.
C
D
3–34
DL205 User Manual, 4th Edition, Rev. B
X0
Time
1.4µs
C0
1.0µs
1.2µs
7.95µs
C100
1.6µs
62.0µs
1.6µs
C101
21.0µs
1.6µs
62.0µs C102
1.6µs
21.0µs
C103
1.4µs
1.2µs
7.95µs
X5
16.0µs
210.5µs
X1 Y0
OUT
LD
K10
OUT V2002
LD
K50
OUT V2006
X10 Y3
OUT
END