
Festo — VTSA-F-CB — 2021-06a
Product overview
17
Time
Description
t
6
Electrical control signal of the valve inactive
t
7
Dead time until exhaust of duct (1)
t
8
Switching point from pressurised state to exhausted state in duct (1)
Tab. 13: Switch-on behaviour of soft start valve
1
2
Fig. 7: Operating pressure [bar] of the soft start valve as a function of the number of valves switching
simultaneously
1
free blow-off (with silencer)
2
with filling (volume = 100 ml)
The times depend on the volume to be filled (configuration of the valve terminal).
The switch-on process takes place in 2 stages:
–
Duct (1) of the valve terminal is pressurised.
The pressurisation time t
4
can be adjusted with the flow control screw on the soft start valve.
If the soft start valve is used for the pilot air supply, duct (14) is filled immediately with the full
operating pressure.
–
When the working pressure in duct (1) reaches half the operating pressure, the soft start valve
releases the full flow rate.
Switching off/exhausting
If the supply voltage is switched off or the output is switched off via the control, the soft start valve
blocks the compressed air supply. Duct (1) is exhausted via the soft start valve.
If the soft start valve is used for the pilot air supply, an additional duct (14) is exhausted via the soft
start valve.