Siemens SINUMERIK 840D Description Of Functions page 235

02.99
 Siemens AG 2000. All rights reserved
SINUMERIK 840D/SIMODRIVE 611 digital Descr. of Functions HLA Module (FBHLA) – 04.00 Edition
The symbol also reveals the principle of position control applied to the valve
spool.
Reset spring
A B
P T
Fail-safe disabled
A
B
P T
Fig. A-3 Graphic symbol
A.1 Servo solenoid valves
Actuating solenoid
Position sensor
Setpoint
U
Valve amplifier with
position control
Fail-safe enabled
A B
P T
A Hydraulics
=0..."10V
E
A-235