Siemens SIMATIC S5 Manual page 313

Glossary
Isolated
Isolation
monitoring
Lightning diverter
Lightning-protec-
tion potential
equalization
Loop resistance
Machine ground
Master
Master interface
Master/slave
procedure
Master-station
number
Master system
Max. retry limit
Glossary-6
On an isolated I/O module the reference potentials of control and load
circuits are galvanically isolated, e.g. by optocouplers, relay contacts or
transformers. Input and output circuits may be grouped. Not to be confused
with "floating".
Facility for monitoring the isolation resistance of a system.
A device capable of wholly or partially diverting a lightning pulse without
losing its integrity.
Comprises those parts of the internal lighting-protection system required to
reduce the potential differentials caused by a lightning pulse, i.e. the
potential-equalization busbars, potential-equalization conductors, clamps,
connectors, air–gap suppressors, lightning diverters and overvoltage arresters.
Total resistance of the feed and return.
The entirety of all interconnected inactive parts of a device. The machine
ground cannot carry a hazardous contact voltage even in the event of a fault.
When in possession of the token, the master may send data to other nodes
and request data from other nodes.
DP masters can be, for example, the IM 308-C or the PG.
Module for distributed I/O. The distributed inputs/outputs are connected to
the programmable controller via the IM 208-C master interface.
Bus access procedure in which only one node is the
other nodes are DP slaves.
The "Master-station number" parameter contains the station number of the
DP master to which a DP slave is assigned and which has parameterized the
DP slave.
The DP master plus all the slaves to which it has read and write access form a
master system.
A bus parameter defining the maximum number of call retries addressed to a
DP slave.
DP master and all
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a