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Glossary
Repeater adapter
Request
Response time
S
SAP
Screen impedance
Segment
Sensors/actuators profile
Service Access Point
Short circuit
Short circuit proof
Simple–Variable
SINEC L2
SINEC L2–DP
Slave initiation
SPM module
Static object list
B-6
Device for a mixed configuration of RS 485 and optical–fiber conduc-
tor transmission hardware.
A request of the FMS master (.req)
Period between an edge at the input and the programmed output signal
change.
Service Access Point
AC resistance of the cable screen. The screen impedance is a characte-
ristic of the cable and is generally specified by the manufacturer.
The bus line between two terminating resistors constitutes a segment.
A segment includes 0 to 32
repeaters.
The PROFIBUS standard, DIN 19245, Parts 1 and 2 covers a wide
range of applications. In a specialized environment, however, such as
the field level, only a limited scope of functions is required. For this
reason, the sensors/actuators profile has been created. It defines the
lower field level and the measuring technology used.
The ET 200U(DP Standard/FMS) is based on the sensors/actuators
profile.
The services available in a layer can be accessed by the (next) higher
layer via a service access point. It represents a logical interface for the
exchange of
protocol data units.
Caused by a fault; it conductively connects conductors that are energi-
zed in normal operation if no resistance is inserted in the faulty circuit.
Equipment is short–circuit proof if it withstands the thermal and dyna-
mic effects of the maximum permissible short–circuit current at a lo-
cation.
Objects of the "Simple–Variable" type cannot be divided up further.
In the ET 200U(DP Standard/FMS), e.g. digital modules and single–
channel analog modules have a "Simple–Variable" object code.
LAN that interfaces PROFIBUS–compatible programmable controllers
and field devices both at the cell and field levels.
SINEC L2 LAN with DP protocol. DP denotes the distributed I/O.
When the slave has received a send request from the FMS master, it
can send an FMS service to the FMS master without any further initia-
tion.
The ET 200U(DP Standard/FMS), for example, informs the FMS ma-
ster of the change of a diagnostics message without any external initi-
tation.
An SPM module can be used for interfacing the distributed I/O with
the SINEC L2–DP bus. The module incorporates an SPM (SIEMENS
PROFIBUS Multiplexer) which generates all the bus messages.
The static object list is an integral part of the
tic object list describes the individual objects.
nodes. Segments can be linked via
object list. The sta-
ET 200U Distributed I/O Station
EWA 4NEB 812 6087–02b
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