Standards and certifications
94
Mobile Panel 40/50 User's manual V1.80
5.4.3
Safety
categories in accordance with
EN
ISO
13849-1:2015 (
Safety
of machinery -
Safety
-
related parts of
control
systems - Part 1: General design principles)
Safety
category (per
EN
13849-1:2015)
Short description
System behavior
B
SRP/CS and/or their protective equipment, as well as their com-
ponents, shall be designed, constructed, selected, assembled and
combined in accordance with relevant standards so that they
can
withstand the expected influence. Basic
safety
principles shall be
used.
Caution!
The occurrence of a fault
can
lead to the loss
of the
safety
function.
1
Requirements of B shall apply. Well-tried components and well-
tried
safety
principles shall be used.
Caution!
The occurrence of a fault
can
lead to the loss
of the
safety
function but the probability of
occurrence is lower than for category B.
2
Requirements of B and the use of well-tried
safety
principles shall
apply.
Safety
function shall be checked at suitable intervals by the
ma-
chine
control
system.
Caution!
The occurrence of a fault
can
lead to the loss
of the
safety
function between the checks.
The loss of
safety
function is detected by the
check.
3
Requirements of B and the use of well-tried
safety
principles shall
apply.
Safety
-related parts shall be designed so that:
•
A single fault in any of these parts does not lead to the
loss of the
safety
function.
•
Whenever reasonably practicable, the single fault is de-
tected.
Caution!
When a single fault occurs, the
safety
func-
tion is always performed.
Some but not all faults will be detected.
Accumulation of undetected faults
can
lead
to the loss of the
safety
function.
4
Requirements of B and the use of well-tried
safety
principles shall
apply.
Safety
-related parts shall be designed so that:
•
A single fault in any of these parts does not lead to the
loss of the
safety
function.
•
The single fault is detected at or before the next demand
upon the
safety
function. If this detection is not possible,
an accumulation of undetected faults is not permitted to
lead to the loss of the
safety
function.
Information:
When a single fault occurs, the
safety
func-
tion is always performed.
Detection of accumulated faults reduces the
probability of the loss of the
safety
function
(high DC).
The faults will be detected in time to prevent
the loss of the
safety
function.
Table 47: Overview of
safety
categories
The following risk graph (per
EN
13849-1:2015, annex A) provides a simplified procedure for risk assessment:
Starting point for the
risk assessment of
the safety-related
part of the controller
Figure 64: Risk graph for determining the PLr for each
safety
function