II - DCE FEL ČVUT v Praze

R
Reference
potential
Response time
Run-time errors
S
Server
SFC
Signal module
Slave
Smart field device
System
diagnostics
System function
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
Potential on which examinations and/or measurements of the voltages in
specific circuits are based.
The average time which elapses between a change at an input and the change
at the corresponding output.
Errors that occur in the programmable logic controller (that is, not in the
process) during execution of the user program.
A server performs a service on request. A server can be, for example, a
program, a module, 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.
System function
Glossary
Signal modules (SM) form the interfaces between the process and the
automation system. There are digital input and output modules (input/output
module, digital) and analog input and output modules (input/output module,
analog).
A slave is only allowed to exchange data with a master if it has been
requested to do so.
All DP slaves, such as ET 200B, ET 200C, ET 200M, etc., are considered to
be slaves.
A complex field device containing a micro processor. Its settings can be set
by the control room using a corresponding parameter assignment tool.
System diagnostics comprises the recognition, evaluation and signaling of
errors which occur within the programmable logic controller. Examples of
such errors include: program errors or module failures. System errors can be
indicated via LEDs or displayed in STEP 7.
A system function (SFC) is a function integrated in the operating system of
the CPU, which can be called in the STEP 7 user program if required.
Glossary-11