Festo VTSA Series, Manual, Page: 97 / 166

4. Commissioning
4−5
Festo P.BE−VTSA−44−EN en 0601a
The pilot air must be applied immediately after it is switched
on at the minimum pressure specified in appendix A, Tab.A/4
for the relevant valves. Otherwise there is no guarantee that
the valve will switch directly (see diagram).
If the pressure is less than the minimum specified, there may
be a delay before the valve is switched, in spite of an electric
signal being present. The slow increase in pressure of the
complete supply does not then affect the actuator. The actua
tor 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 pilot air branched in front of the
start−up valve.
2
Start−up valve for delayed build−up of pressure in
complete supply.
Fig.4/1: Example of valve−cylinder combination with slow
increase in pressure of the complete supply