Siemens Simatic S7-400

A󹪜ect of the “Reaction to CPU Stop” Parameter on the Storage of the Received Message Frames
The response depends on whether or not 󹪞ow control is used.
Table 5-3 Control of Message Frame Storage Without Flow Control
Without Flow Control Saved Frames Frame Just Arriving New Frames
Reaction to CPU Stop: Con‐
tinue
Retained Saved; discarded if the bu󹪜er
is full
Saved until the bu󹪜er is full,
then discarded
Reaction to CPU STOP: STOP Retained Discarded Discarded
Table 5-4 Control of Frame Storage with Flow Control
With Flow Control Saved Frames Frame Just Arriving New Frames
Reaction to CPU STOP: Contin‐
ue
Retained Saved; 󹪞ow control is activa‐
ted if the bu󹪜er is full.
Saved; 󹪞ow control is activa‐
ted if the bu󹪜er is full.
Reaction to CPU STOP: STOP Retained Further data cannot be re‐
ceived because 󹪞ow control is
activated.
Additional data cannot be re‐
ceived because 󹪞ow control is
activated.
See also
Con󹪝guration Data of the 3964(R) Procedure (Page 63)
Managing the Parameter Data (Page 68)
5.4.3 Con󹪝guration Data of the ASCII Driver
Introduction
Using the con󹪝guration data of the ASCII driver, you can adjust the CP440 to suit the
communication partner.
Con󹪝guration Data of the ASCII Driver
With the CP 440: Point-to-Point Communication, Parameter Assignment interface, specify
the parameters for the physical layer (layer 1) of the ASCII driver. Below you will 󹪝nd a detailed
description of the parameters.
Note
The ASCII driver can be used in four-wire mode (RS 422) and two-wire mode (RS 485). At
parameter assignment, you must specify the type of interface (RS 422 or RS 485).
Con󹪝guring and Parameter Assignment the CP 440
5.4 Con󹪝guration data
Point-to-point connection CP 440 Installation and Parameter Assignment
58 Equipment Manual, 03/2022, A5E00057742-AE