Siemens SINAMICS S120 System Manual page 253

Quality of seals
The quality of the seals and guides used for the piston and the piston rod must be
particularly high in order to minimize the friction.
Transitions from static to sliding friction have a particularly adverse affect on the quality of
control accuracy.
FPM
PTFE
Figure A-20
Dead volume
The dead volume is the volume between the cylinder and servo solenoid valve that is not
displaced by one piston stroke. It reduces the natural frequency of the drive and should be
avoided wherever possible.
Cylinder pipework should be kept as short as possible, i.e. the servo solenoid valve should
be mounted directly on the cylinder.
The dead volume is parameterized in the HLA module (p0314, p0315 and p0346 to p0348).
Hydraulic Drive
System Manual, 04/2015, 6SL3097-4BA00-0BP1
Fluororubber
Polytetrafluoroethylene (Teflon)≠
Cylinder
Appendix
A.3 Hydraulic
253