Moog ACV with CANopen bus interface
7 Servo valve functions
Spool position setpoint conditioning / demand value generator
B99224-DV018-D-211, Rev. A, October 2018
145
7.2.6 Directional dependent gain
This function reduces the input signal's gain by a <DirectionalDependentGain_Factor> (0x6341) depending
on the sign of the signal. The function has either an effect on the positive or the negative side of the input sig-
nal. This feature provides compensation for the different extend and retract velocities that result from cylinders
with unequal area and from some load conditions. For a double rod cylinder this compensation factor is typi-
cally 1.0 but can be modified if the load favours one direction. This compensation need only be approximate
but it helps ensure that the closed loop response in both extend and retract directions is symmetrical.
Figure 62: Directional depending gain
The actual flow depends not only on servo valve opening but on pressure loss in the servo valve
and the system load.
x (input)
y(x)
(output)
Spool position
directional depending
gain
input
output
<DirectionalDependentGain_Type>
(0x6340)
<DirectionalDependentGain_Factor>
(0x6341)
num:
#Numerator#
den: #Denominator#
factor: num/den
x (input)
y(x)
(output)
factor >= 1.0
factor < 1.0
slope = den/num
slope = num/den
<Factor>
Input
Resulting output
Input positive
Input negative
Input
positive
Input negative
Table 73: Definition of the directional dependent gain factor values
Factor
1
<
Output
Input
Factor
×
=
Output
Input
=
Factor
1
≥
Output
Input
=
Output
Input
Factor
------------------------
=
