Firmware Drive Functions - Siemens SINUMERIK 840D Description Of Functions

Firmware Drive Functions

4.1 Block diagram of closed-loop control
Overview of
system integration
Control system
Velocity feedforward
control v'
vor
Position set- Position
point x controller
set
Velocity setpoint
v
set
Actual
position
x
act
Fig. 4-1 General block diagram of NC – HLA module – drive system
Achievable
dynamic response
 Siemens AG 2000. All rights reserved
SINUMERIK 840D/SIMODRIVE 611 digital Descr. of Functions HLA Module (FBHLA) – 04.00 Edition
The following block diagram illustrates how the HLA module is embedded be-
tween the NC and the hydraulic drive. The control functions of the module are
shown in greatly simplified form. They are shown in more detail in the following
diagram.
HLA module
Flow feedforward control
Character-
istics com-
pensation
Velocity controller
Actual velocity v
act
Dynamic response is dependent upon:
S
Natural frequency of the servo solenoid valve (see Section 2.3.2)
S
Natural frequency of the drive (see Section 2.3.4)
The greater the natural frequency, the better the achievable dynamic response.
For the purpose of oscillation damping, the natural frequency of the servo sole-
noid valve must be greater than that of the drive.
Drive
Cylinders
Valve setpoint voltage
U
set
D
A
P P
U
p
A
p
B
Servo solenoid valve
A B
P T
Pressure supply
4
Actual position
U
Valve amplifier
4-97