Siemens SIMATIC CP 440 Manual page 69

How is the Storage of the Received Message Frames Controlled by Setting the
"Reaction to CPU Stop" Parameter?
The response depends on whether or not flow control is used.
Table 5-3 Control of Message Frame Storage Without Flow Control
Without Flow Control
Reaction to CPU Stop:
Continue
Reaction to CPU Stop:
STOP
Table 5-4 Control of Frame Storage with Flow Control
With Flow Control
Reaction to CPU Stop:
Continue
Reaction to CPU Stop:
STOP
Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02
Saved Frames
Retained Saved; discarded if the
buffer is full
Retained Discarded
Saved Frames
Retained Saved; flow control is
activated if the buffer is
full.
Retained Further data cannot be
received because flow
control is activated.
Configuring and Parameterizing the CP 440
Frame Just Arriving New Message Frames
Saved until the buffer is
full, then discarded
Discarded
Frame Just Arriving
Saved; flow control is
activated if the buffer is
full.
Further data cannot be
received because flow
control is activated.
New Frames
5-5