Siemens SIMATIC NET CP 5613 Manual page 29

Control Commands
The following control commands can be sent to DP slaves when necessary during
operation:
Control
Commands
FREEZE
UNFREEZE
SYNC
UNSYNC
DP Base Programming Interface for CP 5613/CP 5614
C79000-G8976-C108-02
The states of the inputs are read in and frozen. With this
function, your user program can achieve consistency over
several slaves when reading the input data; in other words,it
is certain that the values read were all set at the same time.
The freezing of the inputs is canceled.
Output is frozen. With this function, your user program can
achieve data consistency over several slaves when writing
output data; in other words,all the slaves use the new
values at the same time.
The UNSYNC command cancels the SYNC command.
Overview of PROFIBUS DP
Description
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