Hypertherm V9 Series Phoenix Rev.11 - Manual (Page 65)

Phoenix 9.76.0 Installation and Setup Manual 806410 65
2 – Machine Setup
With a Proportional Gain too high, the system will be unstable which will result in overshoots, and a generally
“nervous” and shaky axis. This is also referred to as a “hot” control loop.
With a proportional gain too low, the system will respond in a loose or sloppy manner. This can be seen in
the test pattern when the outside corners become rounded and the circle segments do not all meet in the
center.
Integral Gain: Integral Gain improves the positioning accuracy of the control loop.
Integral gain can be used to compensate for static friction or gravity. Excessive Integral Gain can result in
system instability.
For most shape cutting machines, this parameter should be set to zero (0).
Derivative Gain: Derivative Gain helps to dampen sudden changes in velocity.
The higher the derivative gain, the slower the response time to the control loop.
For most velocity loop drives this parameter should be set to zero (0).
Feedforward Gain: Feedforward Gain can be used to drive the following error to zero during machine motion.
In all digital control loops there is a finite amount of error that is introduced by the velocity command.
Increasing Feedforward Gain can reduce this introduced error.
Velocity Gain: When using a current loop amplifier, the internal velocity loop in the CNC can be used to provide
dampening without an external tachometer.
Using the internal velocity loop with a current loop amplifier can result in higher static stiffness, smoother
machine motion, and less overshoot.
Skew Error Tolerance: If the Dual Gantry Axis is installed, the user will be prompted for Skew Error Tolerance. This is
the amount of position error allowed between the master and slave gantry drive axes prior to an error
message being displayed.
 This value should match the value used for the Rail for proper operation.
Encoder Counts per mm (inch): To determine the encoder counts per mm (inch), you will need to know the following
measurements for your encoders:
 counts per revolution of the motor
 gear ratio
 distance of travel in one revolution of the pinion gear
 diameter of the pinion gear when it engages the rack