3 Product Description
Safety function/fail-safe
© Moog GmbH User Manual "D633-A Series" (CA80942-001; Version 1.0, 12/08) 13
3.2 Safety function/fail-safe
Mechanical fail-safe
functions
The mechanical valve fail-safe functions increase the safety of the user if the
command signal fails.
Chapter "3.2.1 Mechanical fail-safe functions", page 13
Mechanical fail-safe state
The valve is rendered in the mechanical fail-safe state if the command signal
fails. The mechanical valve fail-safe state is denoted by the fact that the spool
is in a defined spring-determined position.
Chapter "3.2.1.2 Mechanical fail-safe state", page 14
It is essential to ensure at the machine end that the fail-safe state results in a
safe state in the machine.
The valve must be restarted after its transition into the fail-safe state.
Chapter "3.2.2 Restarting the valve", page 15
3.2.1 Mechanical fail-safe functions
Mechanical fail-safe
functions
The following mechanical fail-safe functions are available:
• Fail-safe function F
• Fail-safe function D
• Fail-safe function M
WARNING
It is essential to observe the notes/information on han-
dling in accordance with safety requirements particularly
in the case of safety-critical applications.
Chapter "2.2 Handling in accordance with safety require-
WARNING
The manufacturer and the operator of the machine are re-
sponsible for ensuring that, when the machine is config-
ured, designed and operated with all of the installed com-
ponents, the latest version of the safety standards rele-
vant to safety-critical applications applicable to averting
damage are observed.
It is vital among other things to ensure that both the individual
components and the complete machine can be rendered in a
safe state.
It is necessary when ordering the valve to establish which mechanical fail-
safe function is to be integrated in the valve.
Which mechanical fail-safe function is integrated in the valve can be as-
certained from the fail-safe identification, i.e., the 6th position in the valve
type designation.
