Siemens Sinumerik 840D Series - Page 244

10.03
A.1 Servo solenoid valves
A-244
 Siemens AG, 2003. All rights reserved
SINUMERIK 840D/SIMODRIVE 611 digital, HLA Module (FBHLA) - 10.03 Edition
Valves with a knee-shaped flow characteristic give the drive greater manipu-
lated variable resolution in the lower signal range (better processing quality)
and, at the same time, offer sufficient flow rate in the upper range (high rapid
traverse velocity).
40%
10%
Q/Q
nom
U/U
nom
Rapid traverse
Machining velocity
Fig. A-8 Flow characteristic with knee, example 40% - knee
ÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎ
Q/Q
nom
U/UU
nom
Spool stroke
40 %
10 %
Fig. A-9 Stepped control window in spool sleeve, example 40% - knee
The knee-shaped characteristic of the valve is linearized in the HLA module to
match it to the closed-loop control of the overall drive (cylinder). No steady-state
operating point should be defined in the knee-point area.
The corresponding valve data are stored in the HLA module and automatically
parameterized when the order number is entered.
Q/Q
nom
U/U
nom
Valve characteristic
Linearized characteristic
compensation
10%
40%
Fig. A-10 Electrical valve knee compensation
Flow
characteristic,
with knee
Linearization of
knee-shaped flow
characteristic
A Hydraulics