Rockwell-automation 1771-DB Basic Module User Manual - Series A Manual de usuario descargar pdf (Pagina 58)

Operating Functions

Chapter 5

5–21

Mode: RUN

Type: CONTROL

The DO – WHILE [rel expr] instruction provides a means of “loop

control” within a module program. The operation of this statement is

similar to the DO – UNTIL [rel expr] except that all statements

between the DO and the WHILE [rel expr] are executed as long as the

relational expression following the WHILE statement is true. You can

nest DO – WHILE and DO – UNTIL statements.

Examples:

SIMPLE DO-WHILE NESTED

DO-WHILE - DO-UNTIL

u10 DO u10 DO

u20 A=A+1 u20 PRINT A=A+1

u30 PRINT A u25 DO

u40 WHILE At4 u30 B=B+1

u50 PRINT “DONE” u40 A,B,A*B

u60 END u50 WHILE Btu3

uRUN u60 B=0

u70 UNTIL A=3

u80 END

uRUN

1 1 1 1

2 1 2 2

3 1 3 3

4 2 1 2

DONE 2 2 4

2 3 6

READY 3 1 3

u 3 2 6

3 3 9

READY

5.4.9

Statements: DO – WHILE

[rel expr] (continued)

1 2 ... 53 54 55 56 57 58 59 60 61 62 63 ... 166 167

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Rockwell-automation 1771-DB Basic Module User Manual - Series A Manual de usuario Pagina 58