Digital Power Amplifier
Series VRD350 and VRD355
Installation Manual
31
IA VRD UK.INDD RH 02.06
Parker Hannifin GmbH & Co. KG
Hydraulic Controls Division
Bypass Controller
See also block diagram on page 19.
The bypass controller is designed as a parallel
circuit of a P-amplifier with an PID-controller. The
processed command signal from U10 is hereby
used directly as an input to the P-amplifier. Follow-
ing calculation, the signal is added to the adjusting
signal of the PID controller. This is supplied with the
control deviation (U12).
This operating mode enables enhanced dynamic
performance with simplified parameter setting.
3.13. Programmable Comparator Function
General Comparator Funktions
The function of the comparators and the compara-
tive value result from the combinations shown in
table below.
P21 and P22 can each be adjusted over the full
range from 0...+9.99V. The setting resolution is
10mV. P21 is responsible for control deviations
≥
0
and P22 for control deviations <0.
The window centre is defined by:
Set = Actual or [Set - Actual] = 0
The window itself by P21 and P22
Setting E2 = 3 activates the bypass, P13 deter-
mines the gain of the bypass loop, P15 is without
any function and P16 sets the P-portion, P17 the
I-Portion and P18 the D-Portion of the PID-con-
troller.
The output delay P23 and P24 (time for switching
output on and off) can be set in steps of 10ms with
the maximum value of 9.96 sec. The opto-decou-
pled comparator output signal can be monitored
at terminal 14b.
Comparator function with E2 = 1, 3 or 4
To implement the monitoring functions with:
• controlled machine functions, and with
• controls (position, speed and pressure controls,
etc.)
Card design
Setting
E2
Enable
Setting
P21/P22
Comparative
value in win-
dow
Comparator
output
LED RESET RAMP
Input
Input
open loop/
0
0V
random
random
0V
off
on
closed loop
open loop
0
24V
≠
0,00
U2 outside
0V
off
on
open loop
0
24V
≠
0,00
U2 inside
24V
flashes
flashes fast
closed loop
0
24V
≠
0,00
U12 outside
0V
off
on
closed loop
0
24V
≠
0,00
U12 inside
24V
flashes
flashes fast
closed loop
1, 3, 4
24V
≠
0,00
U12 outside
0V
off
on
closed loop
1, 3, 4
24V
≠
0,00
U12 inside
24V
flashes
flashes fast
closed loop
2
24V
≠
0,00
U11 outside
0V
see page 29
closed loop
2
24V
≠
0,00
U11 inside
24V
see page 29
open loop
only 0
24V
=0,00
random
0V
off
on
closed loop
1, 2, 3, 4
24V
=0,00
random
0V
off
on