Standards and certifications
Mobile Panel 40/50 User's manual V1.80
95
Parameter S ... Severity of injury
S1
Slight (normally reversible injury).
S2
Serious (normally irreversible injury or death)
Parameter F ... Frequency and/or exposure to hazard
F1
Seldom to less often and/or exposure time is short.
F2
Frequent to continuous and/or exposure time is long.
Parameter P ... Possibility of avoiding hazard or limiting harm
P1
Possible under specific conditions.
P2
Scarcely possible.
Other
L
Low contribution to risk reduction
H
High contribution to risk reduction
PL
r
Required performance level
Table 48: Legend for the risk graph
5.4.4
Safety
categories in accordance with
EN
954-1:1996 (
Safety
of machinery -
Safety
-related
parts of
control
systems - Part 1: General design principles)
The
safety
-related parts of
control
systems must meet one or more of the requirements for five defined
safety
categories. These
safety
categories define the required behavior of
safety
-related
controller
parts with regard to
their resistance to
errors
.
Safety
category
(per
EN
954-1)
Short description
System behavior
B
Safety
-related components must be designed and built in such
a way that they
can
meet the expected operational requirements
(no specific
safety
measures are implemented).
Caution!
The occurrence of a fault
can
lead to the loss
of the
safety
function.
1
Safety
related parts must be designed and built so that only reli-
able components and
safety
principles are used. (e.g. preventing
short circuits by using sufficient distances, reducing the probabil-
ity of
errors
by using oversized components, defining the
failure
route - bias current fail-safe, etc.)
Caution!
The occurrence of a fault
can
lead to the loss
of the
safety
function.
2
Safety
related parts shall be designed so that their
safety
func-
tions shall be checked at suitable intervals by the
machine
control
system (e.g. automatic or manual check during startup).
Caution!
An error between checks
can
result in the
loss of the
safety
function. The loss of the
safety
function is detected during the check.
3
Safety
-related parts shall be designed so that a single fault does
not lead to the loss of the
safety
function. Individual
errors
should
– if possible – be detected the next time (or before) the
safety
function is required.
Caution!
The
safety
function is always retained when
a fault occurs. Some but not all
errors
are
detected. An accumulation of undetected
er-
rors
can
result in loss of the
safety
function.
4
Safety
-related parts shall be designed so that a single fault does
not lead to the loss of the
safety
function. Individual
errors
must be
detected the next time (or before) the
safety
function is required.
If this type of detection is not possible, an accumulation of faults
is not permitted to result in the loss of the
safety
function.
Information:
The
safety
function is always retained when
a fault occurs. The faults are detected in time
to prevent loss of the
safety
function.
Table 49: Overview of
safety
categories
These considerations lead to a
safety
category (B, 1, 2, 3, 4) that specifies how the
safety
-related parts on a
machine
must be designed and implemented.
Information:
The wiring of the stop buttons and enable
switch
es is carried out per
EN
954-1 in the same way as
is carried out in the connection example per
EN
ISO
13849-1. This is the case since the categories of
EN
954-1 have been applied to
EN
ISO
13849-1. It is important to note that the entire concept of the
machine
system must be designed for this.
The
safety
category must be selected based on a risk assessment. This risk assessment is a part of the total risk
assessment for the
machine
.
The following risk graph (per
EN
954-1, annex B) provides a simplified procedure for risk assessment:
