IFM Electronic AC402S, Programming Manual

Page: 201 / 272

SmartPLC SafeLine AC4S with fieldbus interfaces
201
>
10.4.1 Remarks about logical devices
Content
State machines for logical preprocessing ...........................................................................................201
States ....................................................................................................................................................201
State transitions ....................................................................................................................................201
Diagnostic messages ...........................................................................................................................204
43070
>
State machines for logical preprocessing
42985
The safe input signals are preprocessed by means of state machines. Each logical device has its own
state machine which creates a safe process signal from the input signals and the set parameters.
A state machine consists of the following components:

States (
→
States (
→ S.
201 )

State transitions (
→
State transitions (
→ S.
201 )
>
States
42979
Number and type of state result from the scope of the logical evaluation function. The exact
description of the states is given in the documentation of the diagnostic messages of the individual
logical devices.
>
State transitions
42980
The state machine checks in each PLC cycle which conditions for a state transition are fulfilled.
State transitions can be triggered by the following conditions:

Signal states of the input signals (
→
States of the input signals (
→ S.
202 )

System events (
→
System events (
→ S.
203 )

Timer events (
→
Timer events (
→ S.
203 )