Rockwell-automation 1772-LP3 PLC - 2/30 Programmable Controller Progra Manual de usuario descargar pdf (Pagina 294)

File Search and File Diagnostic Instructions

Chapter 17

172

The process continues until the end of the file is reached (position = file

length), at which time the done bit is set. The next false-true transition

starts the search again at the beginning of the file. If the last word of the

file contains a match, the position will equal file length, but the done bit

will not be set. On the next false-true transition, the counter will reset to

000 and the done bit is set. The done bit is reset when the rung goes false.

The search will begin again only after an additional false-true transition.

Instruction Overview:

Output instruction

Key Sequence: [FILE] 21

Counter is manipulated by instruction

Requires 4 user program words

Programming File Search Instruction

WARNING: The counter address specified for the File

Search instruction should be reserved for that instruction. Do

not manipulate the counter preset or accumulated values.

Inadvertent change to these values could result in hazardous or

unpredictable machine operation or run-time error. Damage to

equipment and/or personal injury could result.

To program a File Search instruction, press keys [FILE] 21. A display

represented by Figure 17.2 will appear.

1 2 ... 289 290 291 292 293 294 295 296 297 298 299 ... 345 346

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Rockwell-automation 1772-LP3 PLC - 2/30 Programmable Controller Progra Manual de usuario Pagina 294