IFM Electronic AC402S Programming Manual page 202

SmartPLC SafeLine AC4S with fieldbus interfaces
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States of the input signals
Depending on the type of logical device the following definitions apply:

AS-i slaves
Safe AS-i input slaves transmit their input data as unambiguous code sequences. A code
sequence consists of 2 half-sequences with each half sequence representing a signal channel.

Local I/O interface
At the local I/O interface each input represents a signal channel.
The combination of the two signal channels results in the following states and the respective state
events:
State State / Description
NoChan The signal channels A and B are in the logical state FALSE
ChanA_only Signal channel A is in the logical state TRUE.
Signal channel B is in the logical state FALSE.
ChanB_only Signal channel A is in the logical state FALSE.
Signal channel B is in the logical state TRUE.
ChanAB The signal channels A and B are in the logical state TRUE.
ChanInvalid* The logical value of the signal channels is invalid (e.g. code sequence is incomplete,
code sequence invalid)
* ... Only available for logical devices for AS-i input slaves
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Sequence of the signal changes
The combination of the input signals "ChanA_only" and "ChanB_only" and the state of the parameter
"P_Chan_B_first" allows to define state transitions which consider the sequence of the signal change
at the input channels:
State / Description
ChanA = TRUE UND ChanB = FALSE UND Chan_B_first = TRUE
ChanA = TRUE UND ChanB = FALSE UND Chan_B_first = FALSE
ChanB = TRUE UND ChanA = FALSE UND Chan_B_first = TRUE
ChanB = TRUE UND ChanA = FALSE UND Chan_B_first = FALSE
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Transition event
E_NoChan
E_ChanA_Only
E_ChanB_only
E_ChanAB
E_ChanInvalid
Transition event
E_ChanA; P_ChanB_first = TRUE
E_ChanA; P_ChanB_first = FALSE
E_ChanB; P_ChanB_first = TRUE
E_ChanB; P_ChanB_first = FALSE
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