Festo MPA-FB Series, Manual

Page: 83 / 168

4. Commissioning
4−5
Festo P.BE−MPA−EN en 0502b
The auxiliary pilot air must reach a pressure of 3 ... 8 bar as
soon as it is switched on, Otherwise, there is no guarantee
that the valve will switch directly (see diagram).
If the pressure is less than 3 bar, there may be a delay before
the valve is switched, in spite of an electric signal being pres
ent. The slow increase in pressure of the complete supply
does not then affect the actuator. The actuator would react
suddenly (e.g. a cylinder would extend or retract suddenly,
depending on the valve function).
1
4 2
5 3
14 12
1
2
1
12/14
12/14
3
82/84
2
1
Externally supplied auxiliary pilot air (3 to 8 bar),
branched in front of the safety start−up valve
2
Safety start−up valve (slow build up of pressure of
complete supply)
Fig.4/1: Example of valve−cylinder combination with slow
increase in pressure of the complete supply