Siemens SIMATIC S5 Manual page 309

Glossary
Consistent data
Control command
Cyclic processing
Diagnostics
Distributed I/O
station
DP master
Glossary-2
Data which, on account of its content, belongs together and cannot be
separated is known as consistent data.
The values of analog modules, for example, must always be treated as
consistent data, i.e. the value of an analog module must not be falsified by
being read at two different times.
The IM 308-C can send commands simultaneously to a group of DP slaves in
order to synchronize the DP slaves.
The control commands
synchronization of the DP slaves.
The regular addressing of the DP slaves by the DP master.
The DP master (e.g. the IM 308-C) reads the input data of the DP slaves and
sends output data to the DP slaves.
Cyclic processing corresponds to the RUN and CLEAR operating modes of
the DP master.
The detection, location, classification, indication and evaluation of errors,
faults and messages.
Diagnostics supports monitoring functions that execute automatically during
system operation, thus enhancing the availability of the system by helping to
minimize startup times and idle times.
ET 200 supports a number of diagnostics options, from an overview of the
DP slaves that have generated diagnostic reports to monitoring of individual
channels.
An I/O unit not installed in the central device. A distributed I/O station can
be located at a considerable distance from the CPU. Distributed I/O stations
include:
ET 200B, ET 200C, ET 200L, ET 200M, ET 200U
DP/AS-I Link
S5-95U with SINEC L2 DP interface
other DP slaves from Siemens or other-vendor products
The SINEC L2 DP bus connects the distributed I/O stations to the IM 308-C
master interface or the S5-95U with DP master interface.
A master which functions in accordance with DIN E 19245, Part 3 is
known as a DP master.
FREEZE and SYNC enable event– driven
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a