Standards and approvals

A.2 Safety of electronic controllers

D410
Commissioning Manual, 08/2008 Edition 141
Division into safety-critical and non-safety-critical areas
Nearly all systems contain parts that perform safety-related tasks (e.g. emergency stop
switch, protective grating, two-hand controls). To avoid having to apply safety-related criteria
to the entire controller, it is customary to divide the controller into two areas - one that is
critical to safety and one that is not critical to safety. No special demands are made
concerning safety in the area that is not safety-critical as an electronic fault would not have
any effect on the safety of the system. However, in the safety-critical area, only controllers
and circuits that comply with the relevant regulations, may be used.
Important note
Even if an extremely high level of conceptual safety has been achieved in the design of an
electronic controller - e.g. through implementation of a multi-channel design - strict
adherence to all instructions in the operator's guide is mandatory, as incorrect handling could
invalidate measures taken to prevent hazardous faults or create additional potential hazards.
DANGER
Electrical, magnetic and electromagnetic fields (EMF) that occur during operation can pose
a danger to persons who are present in the direct vicinity of the product - especially
persons with pacemakers, implants, or similar devices.
The relevant directives and standards must be observed by the machine/plant operators
and persons present in the vicinity of the product. These are, for example, EMF Directive
2004/40/EEC and standards EN 12198-1 and -3 pertinent to the European Economic Area
(EEA), as well as accident prevention code BGV 11 and the associated rule BGR 11
"Electromagnetic fields" of the German employer's liability accident insurance association.
These state that a hazard analysis must be drawn up for every workplace, from which
measures for reducing dangers and their impact on persons are derived and applied, and
exposure and danger zones are defined and observed.
The safety information in the Storage, Transport, Installation, Commissioning, Operation,
Maintenance, Disassembly and Disposal sections must also be taken into account.