5. Functional safety engineering
46
Festo P.BE-CMMP-AS-3A-HW-EN 0708NH
5.
Functional safety engineering
5.1
General information and intended use
The CMMP-AS family of servo positioning controllers support the "Safe standstill" safety
function, providing protection against unexpected motion as per the requirements of the
EN 954-1, Category 3 standard.
Bringing the machine to a standstill must be carried out and ensured by the machine con-
trol system. This especially applies to vertical axes without self-limiting mechanics or
counterbalancing.
Based on a danger / risk analysis, as per the machine directives 98/37/EG or EN ISO 12100,
EN 954-1 and EN 1050, the machine manufacturer must plan a safety system for the entire
machine, including all integrated components. This also included the electric drives.
The EN 954-1 standard defines the controller requirements in five different categories
based on the level of risk (see Table 5.1).
Category
1)
Summary of requirements
System behaviour
2)
Principles for achieving
safety
B
The safety-relevant components
and/or protection mechanisms, and
your own components, must be
designed, built, selected, assembled
and combined in such a way as to
conform with the relevant standards
so that they can withstand the ex-
pected influences.
The occurrence of a fault
can lead to a loss of the
safety function.
Primarily characterised
by the selection of com-
ponents.
1
The requirements of category B
must be satisfied.
Proven components and safety prin-
ciples must be used.
The occurrence of a fault
can lead to a loss of the
safety function, but the
probability of a fault
occurring is less than
for category B.
2
The category B requirements have
to be fulfilled and proven safety
principles must be used. The safety
function must be checked by the
machine controller at suitable inter-
vals.
The occurrence of a fault
between such checks can
lead to a loss of the safety
function.
The loss of the safety func-
tion will be detected by the
next check.
Primarily characterised
by the structure
Summary of Contents for CMMP-AS-C2-3A
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