| Kpp |
Position Loop
Proportional Gain.
This is the proportional gain on the loop that surrounds the velocity
loop. |
| Kip |
Position Loop Integral Gain.
This is the integral gain on the loop that surrounds the velocity
loop. |
| Kpv |
Velocity Loop
Proportional Gain.
This is the proportional gain on the velocity loop. |
| Kpff |
Position Feed
Forward Gain.
Compensates for position-based effects in a system. Acts much like
a spring attached to the stage.
(DAC counts / position counts) |
| Kvff |
Velocity Feed Forward Gain.
Scaling factor to match commanded velocity and actual velocity scaling.
If a single encoder is used for the axis feedback (common practice),
then Kvff should be set to 1.0. Kvff can be raised to compensate for
viscous friction effects. Even under severe viscous friction effects,
Kvff rarely exceeds 1.3.
(unitless) |
| Kaff |
Acceleration Feed Forward
Gain.
Compensates for mass in a system.
(DAC counts / (commanded position counts / sample period2
)) |
| Kfff |
Friction Feed Forward Gain.
Compensates for Friction in a stage.
(DAC counts) |
| IMaxMoving |
Position Integral (Kip) Limit
During Motion.
The position integral is clipped to this value while the motion is
taking place. The motion is determined in motion that is based on
commanded velocity. If this is set to zero, the position integral
is effectively turned off during motion. A common way to enhance stability
is to set ImaxMoving to half of Output Limit if it is used. Setting
ImaxMoving to zero can help settling time in non-ideal systems.
(DAC counts) |
| IMaxRest |
Position Integral (Kip) Limit
During Rest.
The position integral is clipped to this value while the motion is
idle. The motion is determined in motion that is based on commanded
velocity. If this is set to zero, the position integral is effectively
turned off when there is no motion. A common way to enhance stability
is to set ImaxRest to half of the Output Limit (if it is used).
(DAC counts) |
| Kdv |
Currently not
used. |
| Output
Limit |
Control Loop Output Limit.
The absolute value of the control output will never exceed this value.
Commonly used to limit current going to a motor. The smaller (more
negative) value contained between Output Limit and Output Limit High
will take precedence. The smaller (more positive) value contained
between Output Limit and Output Limit Low will take precedence.
(DAC counts) |
| Output
Limit High |
Control Loop Output Positive
Limit.
The control output will never exceed this value in the positive sense.
The smaller (more negative) value contained between the Output Limit
and Output Limit High will take precedence.
(DAC counts) |
| Output
Limit Low |
Control Loop Output Negative
Limit.
The control output will never exceed this value in the negative sense.
The smaller (more positive) value contained between Output Limit and
Output Limit Low will take precedence.
(DAC counts) |
| Output
Offset |
Control Loop Offset.
Creates an offset to the control output. Useful for counter acting
gravity on vertical stages. The Output Offset is not removed from
the DAC in an Abort condition.
(DAC counts) |
| Kiv |
Velocity Loop Integral. The velocity loop is make of a PI (proportional
and integral) loop. Kiv is similar to proportional gain in a PID
loop.
Do not use Kiv and Kip together, because changing Kiv will affect
Kip's effect on the control loop.
If you are using Kiv > 0, Kpp acts as the position loop integral.
If you are using Kiv = 0, Kip acts as the position loop integral.
If you are using Kiv > 0 and Kpp > 0, then Kpp acts as a second
derivative on the position loop. This is usually not desired.
|
| VintMax |
Velocity Integral (Kiv) Limit.
The velocity integral is clipped to this value. This value takes effect
regardless of whether or not there is motion on the axis.
Make sure VIntMax is > 0 if Kiv > 0.
Kiv has no effect if VIntMax = 0. |
| Ka0 |
Used only for noise injection
during testing. |
| Ka1 |
Smoothing factor for the velocity
estimate from the encoder.
Ka1 controls a single order low pass filter. Valid values are 0 <=
Ka1 < 1.
What is Ka1? |
