User Manual

3. Installation
3−7
Festo P.BE−SPC200−EN en 0901d
3.2.3 Compressed air reservoir (optional)
For good positioning behaviour during operation, fluctuations
in pressure of max. 1 bar are permitted in front of the propor
tional directional control valve. In order to check the stability
of the supply pressure, you can fit a pressure measuring
point directly in front of the proportional directional control
valve.
· Install a compressed air reservoir (e.g. type VZS−...−B)
between the service unit and the proportional directional
control valve, if the positioning behaviour does not meet
your requirements and if you ascertain fluctuations in
pressure of over 1 bar in front of the proportional direc
tional control valve.
In this way you can reduce fluctuations
in pressure during
operation. You can compensate for slight excesses in the
permitted pressure by using supply tubing with a larger
diameter.
Reservoir volume:
The size of the reservoir volume depends on the cylinder vol
ume of the drive used and should be at least twice as large as
the volume of the cylinder
used.
V
P
=2 * V
Z
V
P
= buffer volume;
V
Z
= cylinder volume (V
Z
= r
2
*  * L
Z
)
L
Z
= cylinder stroke length
r = cylinder diameter / 2