List of abbreviations
C.1 List of abbreviations
3VA molded case circuit breakers with IEC certificate
Manual, 03/2019, A5E03603177010-03
653
Abbreviation
Meaning
RMS
Root Mean Square
RS [interface]
Formerly: Radio Selector; now usually: Recommended Standard
RTU
[Modbus interface]
Remote Terminal Unit
SAS
Short circuit alarm switch
PLC
Programmable logic controller
ST
Shunt trip
STF
Shunt trip flexible
STL
Shunt trip left
T
Test
T [IT systems]
French: Terre (ground)
TC
Test device for molded case circuit breaker or MRCD, suitable for systems
with grounded phase
TCP
Transmission Control Protocol
TD
Test Device
TM
Thermal Magnetic
TMTU
Thermal Magnetic Trip Unit
TRIP-IND
TRIP INDICATOR (trip alarm switch)
TRUE RMS
TRUE root-mean-square
TU
Trip Unit
UAR
Universal release
UL
Underwriters Laboratories Inc.
UR
Undervoltage release
USB
Universal Serial Bus
UPS
Uninterruptible power supply
UVR
Undervoltage release
VDE
Verband der Elektrotechnik Elektronik Informationstechnik e.V. (Association of
German Electrical Engineers)
VDI
Verein Deutscher Ingenieure (Association of German Engineers)
ZSI
Zone selective interlocking