Rockwell-automation 1761 MicroLogix 1000 Programmable Controllers Manual de usuario descargar pdf (Pagina 299)

Programming Reference

B–11

Address DescriptionClassificationBit

S:3L Current Scan

Time

Status

The value of this byte tells you how much time

elapses in a program cycle. A program cycle

includes:

• scanning the ladder program,

• housekeeping,

• scanning the I/O,

• servicing of the communication channel.

The byte value is zeroed by the controller each

scan, immediately preceding the execution of

rung 0 of program file 2 (main program file).

The byte is incremented every 10 ms

thereafter, and indicates, in 10 ms increments,

the amount of time elapsed in each scan. If

this value ever equals the value in S:3H

Watchdog, a user watchdog major error will be

declared (code 0022).

The resolution of the scan time value is +0 to

90 ms (–10 ms). Example: The value 9

indicate

s t

hat 80–90 ms has elapsed since the

start o

f t

he program cycle.

S:3H Watchdog

Scan Time

Dynamic

Configuration

This byte value contains the number of 10 ms

ticks allowed to occur during a program cycle.

The default value is 10 (100 ms), but you can

increase this to 255 (2.55 seconds) or

decrease it to 1, as your application requires.

If the program scan S:3L value equals the

watchdog value, a watchdog major error will be

declared (code 0022).

Reference

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