Data Flow Control; Messages With Process Information - Siemens CP-8000 User Manual

Function Packages
3.1.5

Data Flow Control

The data flow control is that system function which coordinates the communication of mes-
sages within the automation unit.
This function supports:
·

Messages with Process Information

·
Messages with System Information
For the tracking of messages within an automation unit the following test functions are availa-
ble:
·
Data Flow Test
·
Message Simulation
3.1.5.1 Messages with Process Information
IEC 60870-5 distinguishes between the following classes of messages. The type identification
of each message provides information about the class to which a message belongs and with
which methods it is to be distributed:
·
Messages with process information in monitor direction
─ binary information, measured values, integrated totals and bit patterns
·
Messages with process information in control direction
─ commands, setpoint values and bit patterns
The distribution of messages with process information takes place by way of routing (telecontrol
function) or assignment (open/closed-loop control function) based on the message address and
type identification in the message.
Messages with process information, that are to be transmitted to other automation units via pro-
tocol elements, are distributed with the help of the function Automatic Data Flow Routing.
For messages with process information that are to reach sinks within the automation unit
(I/O Modules, open-/closed-loop control function) the routing information or as-signments are au-
tomatically derived from parameters (datapoint address).
Predominantly used are message formats according to IEC 60870-5-101/104 in the public
range with the exception of user data containers. Therefore, for their part the messages are
compatible and interoperable with many other manufacturers.
Messages with process information have a 5-stage message address. Message addresses must
be parameterized at the sources (I/O Modules, open-/closed-loop control function).
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