II - DCE FEL ČVUT v Praze

Glossary
C
CELENEC
Chassis ground
Client
Configuration
Configuration,
central
Configuration,
distributed
CPU
Glossary-2
“Comité Européen de Normalisation Electrotechnique.” The countries of the
European Union as well as Norway and Switzerland are members.
The chassis ground comprises all interconnected inactive parts of a device
which cannot carry any dangerous touch voltage even in the event of a fault.
A client can request a server to perform a service. A client can be a
program, a central processing unit (CPU), or a station (for example, a PC).
The exchange of data between client and server can take place, for example,
via PROFIBUS_DP, in accordance with the master-slave principle. If
there are several clients, the data exchange between client and server can be
coordinated by allocating a separate transfer area to each client.
Assignment of modules to subracks/slots and addresses. A distinction is made
between the actual configuration (modules which are actually connected) and
the nominal configuration. The nominal configuration is defined by the user
in STEP 7 or COM PROFIBUS (or COM ET 200 Windows). The operating
system is thus able to detect incorrectly connected modules when they are
started up.
A configuration is considered to be central if the process I/O units and the
central processing unit are accommodated either in the same subrack or in
extension units in the same or an adjacent cubicle.
A configuration is considered to be distributed if the process I/O units are not
accommodated directly next to the central processing unit either in the same
subrack or in the same or an adjacent cabinet, but are rather physically
separate from it and connected together by means of a communication bus
(e.g. a field bus).
Central processing unit of the S7 automation system, comprising a processor,
an arithmetic and logic unit, a memory, an operating system and an interface
for the programming unit.
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04