Technical data

11.5.2 How the FREE Mode Functions
The following diagram illustrates how the FREE mode functions for output
bytes.
Explanation of Fig. 11.5:
The output byte information to be transmitted is transferred to the output
area of the CP by the user program.
This takes place, either at the end of the PLC cycle using the "PIQ output
or by direct I/O access.
In the FREE mode, the DP polling list processing cycle alone decides when
the data in the output area of the CP are accepted for transmission on the
L2 bus.
PLC
Program
Output
area
PY1 : 7
Data information
transmitted on
the L2 bus
nth processing of
the DP polling
list
(n+1) processing
of the DP polling
list
PY1 : 3
PY1 : 5
PY1 : 00
PY1 : 5
L KH 0007
TPY 1
L KH 0005
TPY 1
L KH 0000
TPY 1
PY1 : 7
L KH 0003
TPY 1
mth PLC cycle
(m+1) PLC cycle
PY1 : 7
PY1 : 5
in CP
Fig. 11.5 CP 5430 TF/CP 5431 FMS Sends to L2-DP Slave
Distributed I/Os (DP) B89060/02
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