Siemens simatic ET 200SP User Manual page 106

Abbreviations
Abbreviation Term
PELV Protective Extra Low Voltage
PN PROFINET
PG Programming device
PS Power supply
PT Power Tags
RAM Random Access Memory
RT Runtime
SD Secure Digital card
SELV Safety Extra Low Voltage
UL Underwriters Laboratories Inc.
USB Universal Serial Bus
106
Meaning
PELV, previously called "extra low voltage with safe isolation",
is a protective measure against electrical shock. See EN
50178.
Compact programming device which meets the special re-
quirements of industry. The PG is fully equipped for program-
ming SIMATIC PLCs.
Power supply
Process tags; tags enable data exchange between the com-
ponents of an automation process, for example, between the
HMI device and the controller.
Main or work memory of a computer with direct access, allow-
ing read access to data and editing.
Memory card
Safety extra-low voltage; protective measure in which circuits
with a rated voltage of up to 50 V AC or 120 V DC are operat-
ed ungrounded and feeds from circuits with a higher voltage
are separated from these by, for example, a safety transform-
er.
Serial bus system for connecting a computer to external de-
vices.
CPU 1515SP PC
Manual, 12/2014, A5E32701806-AA