Acronyms and abbreviations
SM/TTX200/TTX300/SIL-EN TTH200,
TTR200, TTH300, TTF300, TTF350
5
Acronym /
Abbrevia-
tion
English
Description
SIL Safety
Integrity
Level
The international standard IEC 61508 defines four
discrete Safety Integrity Levels (SIL 1 to SIL 4). Each
level corresponds to a range of probability for the failure
of a safety function. The higher the Safety Integrity Level
of the safety-related systems, the lower the probability
that they will not perform the required safety function.
SFF Safe
Failure
Fraction
Proportion of non-hazardous failures; in other words, the
proportion of failures without the potential to put the
safety-related system in a hazardous or impermissible
state.
Low
Demand
Mode
Low Demand Mode
of operation
Measurement type with low request rate. Measurement
type for which the request rate for the safety-related
system is not more than once a year and not greater
than twice the frequency of the retest.
DCS Distributed
Control
System
Control system used in industrial applications to monitor
and control decentralized units.
HMI Human
Machine
Interface
In this case, the HMI is a combined module consisting of
an LCD display with or without a local keyboard.
DTM Device
Type
Manager
A DTM is a software module that supports specific
functions for accessing device parameters, the setup
and the operation of devices, and diagnostics. The DTM
is not executable software. It requires an FDT container
program in order to be activated.
LRV
Lower Range Value Lower measuring range limit
URV
Upper Range Value Upper measuring range limit
Multidrop
Multidrop-Modus
In multidrop mode, up to 15 field devices are connected
in parallel to a single wire pair. The analog current signal
simply serves to supply power to the devices in two-wire
technology with a fixed current of
≤
4 mA.
