Rockwell-automation 1771-IJ_IK IK ENCODER/COUNTER MODULES Manual de usuario descargar pdf (Pagina 40)

5–10 Single Transfer Programming

Publication 1771ĆUM006B-EN-P - June 2002

Figure 5.6

Scan Counter Ć PLCĆ2 Processors

030

CTU

PR003

AC000

030

CTU

PR003

AC000

Branch End

Instruction

15957

The output instruction of both rungs in Figure 5.6 is an up-counter

(CTU) instruction. The first rung, since it is unconditional, is always

true. The second rung, since a branch end instruction by itself is

always false, sets the conditions for the counter as false. Because an

up-counter (CTU) increments for each false to true transition, CTU

030 registers one count each time the program scan occurs.

Scan Counter Ć PLC Processor

Figure 5.7 shows an example scan counter that can be used for a

PLC processor. Because the I/O and program scans of this processor

are asynchronous, this scan counter differs in form and operation

from the scan counter for PLC-2 processors.

Figure 5.7

Scan Counter Ć PLC Processor

200

CTU

PR006

AC000

Rung

11111

20017

No.

15958

1 2 ... 35 36 37 38 39 40 41 42 43 44 45 ... 67 68

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Rockwell-automation 1771-IJ_IK IK ENCODER/COUNTER MODULES Manual de usuario Pagina 40