B-6
ET 200U Distributed I/O Station
EWA 4NEB 812 6087–02b
Repeater adapter Device for a mixed configuration of RS 485 and optical–fiber conduc-
tor transmission hardware.
Request A request of the FMS master (.req)
Response time Period between an edge at the input and the programmed output signal
change.
S
SAP Service Access Point
Screen impedance AC resistance of the cable screen. The screen impedance is a characte-
ristic of the cable and is generally specified by the manufacturer.
Segment The bus line between two terminating resistors constitutes a segment.
A segment includes 0 to 32 ³ nodes. Segments can be linked via ³
repeaters.
Sensors/actuators profile 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.
Service Access Point 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 ³protocol data units.
Short circuit Caused by a fault; it conductively connects conductors that are energi-
zed in normal operation if no resistance is inserted in the faulty circuit.
Short circuit proof 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.
Simple–Variable 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.
SINEC L2 LAN that interfaces PROFIBUS–compatible programmable controllers
and field devices both at the cell and field levels.
SINEC L2–DP SINEC L2 LAN with DP protocol. DP denotes the distributed I/O.
Slave initiation 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.
SPM module 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.
Static object list The static object list is an integral part of the ³ object list. The sta-
tic object list describes the individual objects.
Glossary
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