Serial Transmission Of A Character - Siemens SIMATIC CP 440 Manual

Basic Principles of Serial Data Transmission
2.1

Serial Transmission of a Character

There are various networking alternatives for the transfer of data between two or
more communication partners. The simplest form of data interchange is via a
point-to-point connection between two communication partners.
Point-to-Point Connection
In a point-to-point connection the CP 440 communication processor forms the
interface between a programmable controller and a communication partner. In a
point-to-point connection with the CP 440, the data is transferred serially.
Serial Data Transmission
In serial transmission, the individual bits of each byte of information are transmitted
one after the other in a fixed order.
Drivers for Bidirectional Data Traffic
The CP 440 executes data transfer with communication partners independently via
the serial interface. The CP 440 is equipped with two different drivers for this
purpose.
Bidirectional Data Traffic:
ASCII driver
3964(R) procedure
The CP 440 executes data transfer via the serial interface depending on the
selected driver.
2-2
Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02