Technical data

11.8.3 Cyclic and Acyclic Transmission of
Global_Control Commands
When a control command is sent with the special HDB A-NR: 209, the CPs
distinguish between the two job types in the transferred job field:
➣
Acyclic transmission of control commands
➣
Cyclic transmission of control commands
Acyclic transmission of control commands
With the job type, "acyclic transmission", the CPs send the required control
command once at the end of a DP polling list cycle.
If any of the DP slaves relevant for the control command job are not in the
cyclic data transfer phase with the CPs, the job is not executed and is
acknowledged negatively.
Cyclic transmission of control commands
In contrast to the "acyclic transmission" of control commands, in the job
type "cyclic transmission", once the control command has been activated, it
is sent by the CPs at the end of every DP polling list cycle (Unsync,
Unfreeze).
The cyclic transmission of a control command is terminated by sending a
new control command.
Sending control commands with the job type "cyclic transmission" is only
possible when the mode "cycle-synchronized" was selected during
configuration of the I/O areas with the COM package.
B8976060/02 Distributed I/Os (DP)
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