Siemens Sinumerik 840D Series Function Manual page 34

2 Configuration
2.3 Configuring the hydraulic drive
Q/Q
10%
Fig. 2-8 Diagram of a knee-shaped servo solenoid valve characteristic and its correction in the HLA module
Asymmetrical
flowrate
characteristics
P
A
P
B
O B
P T
Fig. 2-9 Asymmetrical characteristics
2-34
nom
Rapid traverse
U/U
nom
40%
Machining velocity
Note
Recommended selection:
Servo solenoid valves are generally recommended for applications where there
is a clear separation between machining operation and rapid traverse.
It is a good idea to use valves with asymmetrical restriction cross-sections for
differential cylinders or for cylinders that are not arranged horizontally and move
large loads. This improves the hydraulic clamping of the cylinder and adjusts
the controlled system gain of the hydraulic servo-drive for both directions of
travel.
Q
A
v
Q
B
G
SINUMERIK 840D/SIMODRIVE 611 digital, HLA Module (FBHLA) - 10.03 Edition
Q/Q
nom
Valve characteristic
Linearized
characteristic
10%
U/U
40%
compensation
Q
 Siemens AG, 2003. All rights reserved
10.03
nom
U