Rockwell Automation 1772-AF3,D17726.5.2 User Manual AUX FUNCT PROM - Manual (Page 5)

Introduction
Chapter 1
1Ć3
for its proper bit status at a particular step or operation. The desired standard
files can be loaded automatically by a process called a teach routine (described
in the application note PLC-2/30 Diagnostics available from PC Systems
Division, Application Engineering Department).
Program routines for EDC are very similar to a sequencer instruction that
compares a file of input words with a file of standard words for a desired status
at each particular step. Therefore, the routine should only be implemented on a
sequential machine or operation. Keep in mind that the I/O must be at a static
stage for the comparison to be valid. Dynamic I/O or asynchronous machining
operations would result in invalid I/O fault detection.
The AF3 PROM performs the following functions:
File Search - This instruction locates all words in a file whose data is
identical to the data of a specified word.
File Diagnostic - This instruction is used to locate discrepancies between
actual and desired states of I/O or data table words on a bit by bit basis.
Functions