Safety In Application - Danfoss PVG 120 Service Manual

Service Manual

Safety in application

PVG 120 Proportional Valve Group
All makes and all types of control valves (incl. proportional valves) can fail, thus the necessary protection
against the serious consequences of function failure should always be built into the system. For each
application an assessment should be made for the consequences of pressure failure and uncontrolled or
blocked movements.
To determine the degree of protection that is required to be built into the application, system tools such
an FMEA (Failure Mode and Effect Analysis) and Hazard and Risk Analysis can be used.
FMEA – IEC EN 61508
FMEA (Failure Mode and Effect Analysis) is a tool used for analyzing potential risks. This analytical
technique is utilized to define, identify, and prioritize the elimination or reduction of known and/or
potential failures from a given system before it is released for production. Please refer to IEC FMEA
Standard 61508.
Hazard and risk analysis ISO 12100-1 / 14121
This analysis is a tool used in new applications as it will indicate whether there are special safety
considerations to be met according to the machine directives EN 13849. Dependent on the determined
levels conformity this analysis will detirmine if any extra requirements for the product design,
development process, production process or maintenance, i.e. the complete product life cycle.
W
Warning
All makes/brands and types of directional control valves – inclusive proportional valves – can fail and
cause serious damage. It is therefore important to analyze all aspects of the application.
Because the proportional valves are used in many different operation conditions and applications,
the manufacturer of the application is alone responsible for making the final selection of the products –
and assuring that all performance, safety and warning requirements of the application are met.
The process of choosing the control system – and safety levels – is governed by the machine directives
EN 13849 (Safety related requirements for control systems).
520L0247 • Rev JA • May 2014 7