Rockwell-automation 1772-AF3,D17726.5.2 User Manual AUX FUNCT PROM User Manual download pdf (Page 14)

File Search Instruction

Chapter 3

36

Figure 3.8

Example Minimum Logic

010

0405

0400

0405

Function

Funtion Number:

Data Addr:

Rresult Addr:

Execute Aux

Control bits of the file search instruction are located in the result word, bits 17

thru 14 as follows.

Bit: 17

Function: Enable (EN)

Description: Your program logic must cause a false-to-true transition of the

enable bit for the instruction to operate. Program logic must reset then set the

enable bit before the instruction can search the file for the next match. This is

the only bit that your program logic can manipulate.

Bit: 16

Function: Last State (LS)

Description: The instruction toggles this bit from off to on to off each time the

instruction is enabled and then reset after each match. The last state bit is used

by the instruction to remember the status of the enable bit in the previous scan,

and to prevent the instruction from executing the next search until the enable bit

undergoes another false-to-true transition.

Bit: 14

Function: True (TR)

Description: The instruction sets this bit in the same scan that it finds a match

between data in the match word and data in a file word. The instruction resets

this bit in the next scan. You can consider its operation a one-shot. Your

program logic should detect the setting of this bit as a condition for initiating

the logic associated with a match of data.

Function of Control Bits

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 31 32

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Rockwell-automation 1772-AF3,D17726.5.2 User Manual AUX FUNCT PROM User Manual Page 14