Siemens SINAMICS S120 System Manual page 239

Pressure amplification
The quality of zero overlap at the middle position is represented by the pressure
amplification.
This states what percentage of the control spool deflection from the hydraulic zero point is
needed to achieve a pressure differential of 80% system pressure at the closed load ports.
The values typically lie in the 1...3% range.
The following graphical representation of the measurement, which covers all 4 control edges,
shows this clearly.
Figure A-5
Hydraulic Drive
System Manual, 04/2015, 6SL3097-4BA00-0BP1
Pressure amplification
Appendix
A.3 Hydraulic
239