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1 General Overview
05.91
1.2.3 Reaction to interrupt and alarm signals
In the flag area the PLC user program is informed of the alarm signals that have been affected
by edge changes and of the current edge status, either rising or falling. Branching can be ef-
fected in OB 3 with reference to this information.
1.3
PLC interfaces
The individual interfaces of the PLC are briefly outlined and their delimitations are explained in
the following Subsections. The interface signals are described in Section 3.
1.3.1
Interfaces, definition and overview
"PLC interface" is used here to refer to an interface between the PLC user program and a
communication partner. The abbreviation "PLC" is therefore often used to denote the PLC
user program when describing the interfaces.
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SINUMERIK 880 (PJ)