Designation
Description
Parameters
Index
pRef
Pressure reference value
pRef
2847
2
pressAct
Pressure actual value
pAct
2847
0
Pressure actual value
pAct2
2847
1
One of the two values, selectable using
P
2840[3]
Pressure difference=
pAct - pAct2
2847
2847
0
1
Qmax
Max. volumetric flow rate limit
QMax
Max. volumetric flow rate setpoint
QRef
One of the two values, selectable with
P 2840[6, 7]
2850
2847
8
3
Qmin
Min. volumetric flow rate limit
QMin
Min. volumetric flow rate setpoint
QRef
One of the two values, selectable with
P 2840[6, 7]
2850
2847
7
3
Kp, τn
PI(D) pressure controller (derivative term
not implemented at the time of writing)
2850
0-4
nRefPump
Pump speed setpoint
2843
9
nmin
nmax
Speed limit pressure control
2851
2851
5
6
nRefMot
Motor speed setpoint
2843
12
PressWindow
Pressure window “Pressure reached”
2850
9
Legend for “Structure of pressure control”
ID
Index Name
Unit
Description
2850
HYD_PressCon
Hydraulic pressure control parameters
2850
0
Kp
rpm/bar Gain
2850
1
KpScale
Gain scaling
Gain scaling
2850
2
Tn
ms
Integration time constant
2850
3
Tv
ms
Rate time
2850
4
Tp
ms
Integral-action time
Table 7.80: “Hydraulic - pressure control” parameters
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
198
7 Control
ID
Index Name
Unit
Description
2850
5
pMin
bar
Minimum permissible pressure
2850
6
pMax
bar
Maximum permissible pressure
2850
7
QMin
l/min
Minimum flow rate
2850
8
QMax
l/min
Maximum flow rate
2850
9
PressWindow
bar
Pressure control parameters
2850
10
decmpLvl
bar
Level for active decompression
2850
11
decmpRate
bar/s
Rate for active decompression
2850
12
pActScale
Scaling for pAct
2850
13
pAct2Scale
Scaling for pAct2
2850
14
pRange_k
%
Pressure range threshold
2850
15
pRange_midpoint
bar
Pressure range midpoint
2853
HYD_PressConScale
Scaling of the properties of the pressure control gain
2853
0
pMin
bar
Minimum permissible pressure of the characteristic
2853
1
pMax
bar
Maximum permissible pressure of the characteristic
2853
2
Nval
Number of interpolation points
2853
3
Type
Interpolation type
2853
4
Table0
%
Scaling Table Value 0
2853
5
Table1
%
Scaling Table Value 1
2853
6
Table2
%
Scaling Table Value 2
2853
7
Table3
%
Scaling Table Value 3
2853
8
Table4
%
Scaling Table Value 4
2853
9
Table5
%
Scaling Table Value 5
Table 7.80: “Hydraulic - pressure control” parameters (continue)
7.11.8 Volumetric flow rate control
7.11.8.1 Volumetric flow rate control with pressure limitation
If the reference variable for the volumetric flow rate that needs to be set is
QRefInput, the implemented volumetric flow rate control can be used. Generally,
QRefInput can be converted to an equivalent motor setpoint speed nRefPump
using the displacement volume and QLeak can be disregarded during the process.