MITSUBISHI ELECTRIC 700 Series - Manual (Page 67)

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Overview
3.1 Overview
3.1.1 Outline of Operation Processings
This section outlines processings performed from when the inverter is powered on
until a sequence program is executed.
The built-in PLC function processings are roughly classified into the following three
types.
(1) Initial processing
Pre-processing for executing sequence operation. This processing is executed
only once when power is switched on or a reset is performed.
(a) The inputs/outputs are reset and initialized.
(b) The data memories are initialized (the bit devices are turned off and the word
devices are cleared to 0).
(c) Self-diagnostic checks are made on the built-in PLC function parameter
setting, operation circuit, etc.
(2) Sequence program operation processing
The sequence program written to the built-in PLC function is executed from step 0
to an END instruction.
(3) END processing
Post-processing for terminating one sequence program operation processing and
return the sequence program execution to step 0.
(a) Self-diagnostic checks are performed.
(b) The present values of the timers are updated and their contacts are turned
on/off, and the present values of the counters are updated and their contacts
are turned on.
REMARKS
The built-in PLC function parameters can be confirmed from GX Developer. (Refer
to the GX Developer Operating Manual.)