Rockwell-automation 1771-DB Basic Module User Manual - Series A Manual de usuario descargar pdf (Pagina 54)

Operating Functions

Chapter 5

5–17

Mode: COMMAND/RUN

Type: CONTROL

The CLEARS statement resets all of the module’s stacks. The

control, argument and internal stacks all reset to their initialization

values. You can use this command to reset the stack if an error occurs

in a subroutine.

Important: When the CLEARS statement is LISTed it appears as

CLEAR S.

Mode: COMMAND AND/OR RUN

Type: CONTROL

CLOCK1

The CLOCK1 statement enables the real time clock feature resident

on the BASIC Module. The special function operator TIME is

incremented once every 5 milliseconds after the CLOCK1 statement is

executed. The CLOCK1 STATEMENT uses an internal TIMER to

generate an interrupt once every 5 milliseconds. Because of this, the

special function operator TIME has a resolution of 5 milliseconds.

The special function operator TIME counts from 0 to 65535.995

seconds. After reaching a count of 65535.995 seconds TIME

overflows back to a count of zero. The interrupts associated with the

CLOCK1 statement cause the module programs to run at about 99.6%

of normal speed. That means that the interrupt handling for the REAL

TIME CLOCK feature uses about .4% of the total CPU time.

CLOCK0

The CLOCK0 (zero) statement disables or “turns off” the real time

clock feature. After CLOCK0 is executed, the special function operator

TIME no longer increments. CLOCK0 is the only module statement

that can disable the real time clock. CLEAR and CLEARI do NOT

disable the real time clock, only its associated ONTIME interrupt.

Important: CLOCK1 and CLOCK0 are independent of the wall

clock.

5.4.4

Statement: CLEARS

5.4.5

Statements: CLOCK1

and CLOCK0

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Rockwell-automation 1771-DB Basic Module User Manual - Series A Manual de usuario Pagina 54