Communications configuring
3-256
System- and communication configuring D7-SYS - SIMADYN D
Edition 12.2003
•
As soon as the appropriate parameter block is to be executed (when
cascading several parameter blocks), it transfers its task to the central
PKW block.
•
The cascading defines when a parameter block is to be executed and
when it can transfer its task.
(A task is transferred, if the block has been activated, i.e. if the input
EN is a logical 1, and the value at input IC has changed).
•
A parameter block remains active (i.e. it is being executed) until it
receives a response regarding its task from the central PKW block.
Then it activates the following parameter block, configured in the
cascade, by inverting its cascade output QC.
Data level
••••
Receive
block
Transmit
block
PKW
central
block
@DPH
Parameter
block
DPI
Parameter
block
DPI
Parameter
block
DPI
Parameter
block
DPI
CRV
CTV
PKW responses
PKW tasks
to the
device
from the
device
MMI level
...
Fig. 3-104 Mode of operation of the PKW blocks
Delay time limiting, i.e. limiting the delay between the task transfer and
the response being accepted is not possible for parameter blocks, but
only for the central block. The parameter blocks wait, unconditionally, for
a response from the central PKW block. The configuring engineering
must ensure, that several parameters cannot simultaneously, transfer
tasks to a central PKW block (he must also ensure that there is no
overlapping).
The central PKW block first processes a response. If differentiates
whether it received a parameter response or a parameter change report
from the associated receive block. It transfers a response to the currently
active parameter block; it outputs a parameter change report at its own
I/O.
After processing the response, the central PKW block processes a task. It
converts the task, received from the parameter block, formally
Delay time limiting
Response
processing
Task processing