Firmware Drive Functions - Siemens Sinumerik 840D Series Function Manual

Firmware Drive Functions

4.1 Block diagram of closed-loop control
Integration in
overall system
Control
Velocity feedforward
control v'
forw
Position
Position
controller
setpoint x
set
Velocity
setpoint v
set
Actual
position x
act
Fig. 4-1 General block diagram of NC - HLA module - drive system
Possible
dynamic response
 Siemens AG, 2003. All rights reserved
SINUMERIK 840D/SIMODRIVE 611 digital, HLA Module (FBHLA) - 10.03 Edition
The following diagram shows how the HLA module is embedded between the
control system and the hydraulic drive. The control functions of the module are
shown in greatly simplified form. They are shown in more detail in the diagram
on the following page.
HLA module
Flow feedforward
control
Characteristics
compensation
Velocity controller
Actual
velocity v
act
The dynamic response is dependent on:
S
Natural frequency of the servo solenoid valve (see Subsection 2.3.2)
S
Natural frequency of the drive (see Subsection 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
Cylinder
Valve setpoint
voltage U
set
D
O
P P
U
p
A
p
B
Servo solenoid valve
O B
P T
Pressure supply
4
Actual position value
U
Valve
amplifier
4-95