Checking The Open Loop Gain; Filter Alignment - Parker Compax3 Fluid T40 Operating Instructions Manual

Parker EME

Checking the open loop gain

In order to verify the open loop gain calculated from the component data. In the
ideal case, the axis achieves the setpoint speed in both directions during open loop
operation.
Oscilloscope settings:
Setpoint speed of the setpoint generator
Actual speed (filtered)
Initially compensate a possible valve offset. In order to do this the value
optimization Output chain X
standstill.
Afterwards, the axis is moved for example with the aid of the jog funciton in the
setup window. When comparing the setpoint speed and the actual speed you have
distinguish between four different cases:
Setpoint speed> actual speed, positive travel direction:
The open loop gain is too small
increase Gain factor positive.
Setpoint speed< actual speed, positive travel direction:
The open loop gain is too high
decrease Gain factor positive.
Setpoint speed> actual speed, negative travel direction:
The open loop gain is too small
increase Gain factor negative.
Setpoint speed< actual speed, negative travel direction:
The open loop gain is too high
decrease Gain factor negative.
Now the axis must move in open loop with the preset speed.

Filter alignment

Especially when using feedback systems with low resolution, a filter alignment is
necessary. With high resolution systems, this step might not be necessary.
Oscilloscope settings:
Actual speed (filtered)
The Parameter Optimization
increased until there are no longer any spikes in the speed signal during the open
loop movement of the axis.
ATTENTION: too strong filterung causes additional deceleration and
phase shifting in the control loop and may later make the control
instable! Filter as moderately as possible.
ATTENTION: when using analog position feedback systems, you
should at first perform an input filtering. Optimization
Inx Filter.
192-121102 N04 June 2008
Offset is changed until the axis comes to a
Optimization
Optimization
Optimization
Optimization
Controller dynamic Filter 2 speed actual value is
Setting up Compax3
Output chain X
Output chain X
Output chain X
Output chain X
Analog input
101