User's Manual

SIMATIC Modular Controllers 59
Point-to-point connection
Point-to-point link via communications processors (CPs) is an
extremely powerful and low-cost alternative to bus systems.
The advantage of point-to-point links over bus systems is es-
pecially pronounced when only a few (RS 485) devices are to
be connected to the SIMATIC S7.
The CPs can also easily link third-party systems to the
SIMATIC S7. Thanks to the great flexibility of the CPs, different
physical transmission media, transmission rates or even cus-
tomized transmission protocols can be implemented.
The CPs have a rugged plastic housing with LEDs for displaying
operating states and faults.
For each CP there is a configuring package on CD with elec-
tronic manual, parameterization screen forms and standard
function blocks for communication between the CPU and
the CP.
The configuration data are stored in a system block and
backed up in the CPU. When modules are replaced, the new
module is therefore immediately ready for use.
With the S7-400 point-to-point link modules, adaptation to
the physical transmission media is achieved by plugging in the
relevant interface submodules, without the need for external
converters.
Point-to-point links for SIMATIC S7-400
Scanner
Barcode
reader
Process
controller
SIMOVERT
SIMOREG
Modem
PC Printer Robot
control
BDE
terminal
3rd party
PLC
G_ST70_XX_00687
SIMATIC S7
Technical data: Point-to-point connection
Application High-speed response
with low data volumes
Interconnection
Low-cost:
With one variable
interface
High-speed:
With two variable inter-
faces
Transmission rate High (115 200 bit/s) Low (38 400 bit/s) High (115 200 bit/s)
Loadable protocols
(Order No. group: 6ES7 340-)
MODBUS Master (-1AA.),
MODBUS Slave (-1AB.),
Data Highway (-1AE.)
Module CP 440 CP 441-1 CP 441-2
Order No. group: 6ES7 440-1. 441-1. 441-2.
Physical transmission media
RS 232C (V.24) All transmission methods, all interface modules,
plug-in, serial
20 mA (TTY)
RS 422/485 (X.27) ● (up to 32 nodes)
Integrated transmission protocols
ASCII
●
Printer driver
●
3964 (R)
●
RK 512
●
SIMATIC_Controller_032011_en.book Seite 59 Montag, 4. April 2011 2:35 14
© Siemens AG 2011