SAFETY MANUAL - Tuv-fs.com

SAFETY MANUAL
RS-232C,
RS-422,
RS-485
RTU
Safety
SFC
Standard interfaces introduced by the Energy
Industries Association covering the electrical
connection between data communication
equipment. RS-232C is the most commonly
used interface,. However, RS-422 allows for high
transmission rates over greatly increased
distances.
Remote Telemetry Unit
Where TÜV certification is a requirement, the
Safety Chapter prescribes how to use the TMR
system in a safety-related application.
Sequential Function Chart. A IEC1131 language
that divides the process cycle into a number of
well-defined steps separated by transitions.
SIL Safety Integrity Level. One of four possible
discrete levels for specifying the safety integrity
requirements of the safety functions to be
allocated to the safety-related systems. SIL4
has the highest level of safety integrity; SIL1 has
the lowest.
Slot
A slot is the term given to the physical
allocation of a module within a 483mm (19 inch)
frame.
SmartSlot Spare module slot position wired, and
configured to enable any one of a number of
modules of the same type to be ‘hot’ replaced as
necessary.
SOE
Software
(Application
Software)
Sequence of Events
Software specific to the user application.
Generally, it contains logic sequences,
permissives, limits, expressions, etc. that
control the appropriate input, output,
calculations and decisions necessary to meet
system safety functional requirements.
ST Structured Text. A high level IEC1131
structured language with a syntax similar to
Pascal. Used mainly to implement complex
procedures that cannot be expressed easily
with graphical languages.
Swingframe
Synchronous
System
An empty hinged metal surround, designed to
contain 483mm (19 inch) standard equipment.
A data-communication term describing the
method by which signals between computers
are timed. In synchronous communications, a
pre-arranged number of bits is expected to be
sent across a line per second. To synchronise
the sending and receiving machines, a clocking
signal is sent on the same line by the
transmitting computer. There are no start or
stop bits in synchronous communications.
Sophisticated software package which can be
Doc No P8094
Issue 14 September 2003
Page xiv