12.
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OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU
12.1.7 END processing
This is a post-process to finish one cycle of operation processing of the sequence program
and to return the execution of the sequence program to step 0.
(a) Self-diagnostic checks are performed for fuse blown, module verify, or low
battery. (Refer to Section 9.3)
(b) When data read/write is requested from a peripheral device or an intelligent
special function module (computer link module, serial communication module,
Ethernet module, etc.), data are exchanged between the PLC CPU and the
peripheral device or intelligent special function module.
(c) Refresh processing is performed when a refresh request is issued from a
network module or a link module.
(d) When the trace point for sampling trace is set to each scan (after execution of
END instruction), the status of the set device is stopred into the sampling trace
area.
(e) Refresh processing based on the MELSECNET/MINI-S3 automatic refresh
function is performed. (Refer to Chapter 7))
POINT
(1) If the constant scan function (see Section 10.2) is set, the END processing
time result is retained during the period between completion of END
processing and start of the next scan.
(2) If a low-speed execution type program (see Section 12.1.3) is executed, low-
speed END processing is performed separately from normal END processing.
In low-speed END processing, the special relays and special registers for low-
speed execution programs are set.
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