ServoLoopGainNormalizationFactor Parameter
Default Value: 0.0
Minimum Value: 0.0
Maximum Value: None
Units: None
Type: double
Tip: To automatically tune and optimize an axis in a new or existing system, you can use the EasyTune feature. This feature is in the Axes > Servo section of the Configure workspace in Automation1 Studio. After EasyTune completes, the optimized servo gains and servo filters are committed to the controller.
Servo Motors
The ServoLoopGainNormalizationFactor parameter uses the values of the motor force or torque constant, the mechanical transmission ratio, and the resolution of the feedback sensor to scale the ServoLoopGainK Parameter into engineering units.
If ServoLoopGainNormalizationFactor is set to 1, the base unit of ServoLoopGainK is 
. The goal is to specify a ServoLoopGainNormalizationFactor to transform ServoLoopGainK into a physically-meaningful engineering unit of stiffness at the workpoint.
When you set this parameter to the correct value, the units of the servo loop gains will be the same as the documentation equation examples.
Where:
MechanicalTransmissionRatio is the mechanical transmission ratio from the motor to the workpoint.
Kt is the motor force or torque constant 
CountsPerEngineeringUnit is the number of counts per engineering unit at the workpoint (payload) 
Kteff equals Kt if the MechanicalTransmissionRatio == 1 (direct drive)
The position engineering unit (defined by CountsPerEngineeringUnit) that defines the servo stiffness can be different than the commanded position unit (defined by CountsPerUnit).
The ServoLoopGainK stiffness unit should be:
- Linear stage:
- Rotary stage:
- Galvanometer:
Since the numerator of Kt has N or N · m in it, the engineering position unit should be:
- Linear stage: mm
- Rotary stage: rad
- Galvanometer: krad
Use the equations that follow to calculate the ServoLoopGainNormalizationFactor parameter values for different types of stages.
Direct Drive Linear Stage
Screw Drive Linear Stage
Direct Drive Rotary Stage
Gear Drive Rotary Stage
Gantries
When you use the Current Command Coupling Control method, the ServoLoopGainNormalizationFactor value for the axis under servo control (the leading axis) is a multiple of the value it would be under normal servo control. The ServoLoopGainNormalizationFactor values for the axes that receive the cloned current command from the leading axis does not matter because those axes are not truly under servo control. In the example of an H-bridge gantry with two Direct Drive Linear spars:
Where:
is the force constant of the motor of the leading axis.
When you use the Decoupling Control method to control gantries, the Linear (R) logical axis is also a multiple of the value it would be under normal servo control. In the example of an H-bridge gantry with two Direct Drive Linear spars:
Where:
is the force constant of the motor on Spar 1.
The ServoLoopGainNormalizationFactor calculations for Yaw (Theta) axis of gantries under Decoupling Control depend on the mechanical construction of the gantry. For a rigid H-bridge gantry made from two Direct Drive Linear spars:
Where:
MultiplicationFactor is the feedback multiplication factor for analog encoders. Use 1 for digital encoders.
FeedbackResolution is the resolution of the feedback device in microns.
GantryFeedbackSeparation, for Rigid gantries, is the distance between the spar feedback devices in millimeters.
GantryMotorSeparation is the distance between the spar motors in millimeters.
ForceConstantPeak is the linear force constant of one spar motor.
Stepper Motors
The ServoLoopGainNormalizationFactor parameter uses the resolution of the feedback sensor and the microstepping resolution of the motor to scale the ServoLoopGainK parameter.
When you set this parameter to the correct value (see below), the units of the servo loop gains will be the same as the documentation equation examples.
Use the equations that follow to calculate the ServoLoopGainNormalizationFactor parameter values for stepper motors.
