November 17
26
s
afety
& s
eCurIty
Functional Safety system developments
from MCU vendor point of view
By Thomas Kellermann,
Renesas
This article highlights the importance
of Functional Safety for system
development, already a complex
exercise and becoming even more
complex. Component manufacturers
will play a decisive role, especially
MCU vendors. Application developers
will need support for high-end
functional safety systems, but they
can accelerate development and save
engineering costs.
n
The term Functional Safety has become a
topic of great interest. Functional Safety gen-
erally means that malfunctions of the oper-
ating systems or applications that lead to
any kind of threat or even accident have to
be avoided. Of course, this basically includes
human health and environment, but also
material integrity can be of high interest. In
other words, functional safety is that part of
the overall safety that depends on failure-free
operation of a system.
But how can such dangerous events be
avoided? For sure, on the one hand it is quite
important to minimize the risks. Actually, the
risk minimization is only reasonable to a cer-
tain extent. Thus, it is fundamental in the field
of functional safety to identify and under-
stand potential risks and failure causes of a
system. If ideally all potential failure causes
are known and the consequences understood
it is possible to define usable countermeasures.
Thus, failures are detected before a hazardous
event occurs and with the needed functional
safety reaction the safe state is initiated. The
safe states can be quite different depending on
the application. A heater can be made safe by
simple power-off, a safety barrier might need
to be to be closed, a crane might be made
safe by freezing the current position, and a
motor control unit could need a specific pow-
er-down procedure. Just looking at the differ-
ences between safe states reveals the variety of
functional safety applications. Every applica-
tion is different and has its own peculiarities
and thus potential failure causes and related
safe states. This makes a functional safety
analysis very complicated and interesting at
the same time.
As mentioned at the beginning functional
safety is currently one of the major trends
in lots of industries. The topic is much more
present than some years ago and still rapidly
growing. Actually, functional safety should
grow up together with the usage of IT in safe-
ty-critical applications. In reality it needed
some experience and unfortunately also some
accidents to lead to the beginning of func-
tional safety in the early eighties. Since then
we have had a significant and constant growth
of IT and embedded systems that control safe-
ty-related applications.
For sure the presence of functional safety in
the last few years is quite different for specific
areas. In some special sectors, such as process
industry, it has already been considered for a
long time. Later the automotive area needed
functional safety which is established and well
known today. For getting embedded systems
into our cars more and more functional safety
was needed. The situation is similar in every
sector where humans are transported by any
kind of electric or electronic controlled device,
no matter if on water, in the air or on railways.
Human lives are reliant on correctly working
systems thus functional safety is vital.
Today additional areas are accelerating the
growth of overall functional safety devices.
One reason is that it is driven by current
major trends like Industry 4.0, Internet of
Things and Smart Home/Building. A lot of
new safety applications arise in these sectors
due to increased integration of intelligence.
In parallel the existing safety applications get
much more complex.
Industry 4.0 moves factories to intelligent
and flexible production clusters. Separation
and encapsulation of safety-critical work-
flow steps is continuously being reduced.
Man and machine are working side-by-side
or even hand-in-hand. Autonomous sys-
tems in decentralized real-time production
require build-in safety functionality to allow
such safe human-machine collaborations to
reduce physical safety barriers like safety locks
or safety fences. All this leads to an increase
in functional safety related applications. Due
to the Internet of Things, embedded systems
and generally IT are now conquering a wider
area of home and building automation. This
increases the potential risks of all this addi-
tional intelligence.
