Siemens SINUMERIK 840D Description Of Functions page 239

02.99
Rated flowrate
Asymmetrical
characteristics
P
A
P
B
A B
P T
Fig. A-11 Asymmetrical characteristics
Dynamic response
 Siemens AG 2000. All rights reserved
SINUMERIK 840D/SIMODRIVE 611 digital Descr. of Functions HLA Module (FBHLA) – 04.00 Edition
This describes the maximum flowrate with fully opened valve in relation to a
pressure drop of ∆p=35 bar per control edge.
Typical values are:
S
Size 6: Q=4...40 l/min
S
Size 10: Q=50...100 l/min
With pilot-controlled valves, the rated flowrate is related to ∆p=5 bar per control
edge. (Reduction in losses with higher flow rates.)
The values for sizes 10 and 16 are then as follows:
S
Size 10: Q=55...85 l/min
S
Size 16: Q=120...200 l/min
The flow under other pressure conditions is calculated according to the law of
flow by the following formula:
Q =Q
X nom
The speed of the cylinder is determined by a combined throttling effect at the
inlet and outlet. The cylinder is clamped hydraulically at both ends.
In order to ensure adequate effectiveness of the outlet throttle on cylinders with
single-ended piston rod and draw load, larger servo solenoid valves with asym-
metrical characteristics are available as alternatives.
Q
A
v
Q
B
G
The dynamic response characteristics indicate how fast the valve can react to
setpoint changes.
One characteristic that is indicative of dynamic response is the actuating time.
This defines how much time the valve spool needs to open the valve in re-
sponse to a step change in the input signal from 0 V to 10 V.
A.1 Servo solenoid valves
∆p
@
X
∆p
nom
–U
E
A Hydraulics
+Q
+U
E
–Q
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