[HLKTech]

Hi Tom.

We are currently in the process of setting up a 4th axis using NSK ESA23 Megatorque motor and driver.
We already have the motor and driver successfully enabled and driven by KFlop using open collector CW/CCW mode on connector JP6. We can command movement through KMotion CNC however are still not clear on the appropriate axis parameter setup in the Trajectory Planner. We need to specify the movement in degrees rather than inches.

The motor has a resolver resolution of 614400 pulses/rev. This would indicate (614400 / 360) = 1707 counts / degree however in kmotion cnc, a G0 command does not move the motor the correct angle. What we desire is to command the motor to rotate a specified number of degress. We have the Degrees radio button Checked for the 4th (A) axis.

Questions
1. How to calculate the Counts/Deg value in the axis parameters?
2. What would be appropriate values for the velocity, acceleration?
3. What effect does the Radius setting have on these values?
4 Does the DRO in KMotionCNC for the A Axis now reflect degrees or is it still in inches?
5 Do the Step Response values in KMotion software effect these settings?

Thank you for your help
Best regards

[TomKerekes]

Hi HLKTech,

How to calculate the Counts/Deg value in the axis parameters?

Your calculation looks correct to me. How far is it off? If you are confusing quadrature transitions with quadrature cycles the the result would be off by a factor of 4.

What would be appropriate values for the velocity, acceleration?

That would depend on the capabilities of your system. Use the KMotion Step Response Screen to test/verify what works well.

What effect does the Radius setting have on these values?

The radius settings affect the feedrate calculations. For situations such as engraving on a cylinder (constant radius) where the cylinder rotates and there is also a linear axis along the cylinder, then a simple feedrate can be specified and KMotion is able to plan the rotation and linear motion in a way to maintain the feedrate at the tool tip.

For configurations that do not operate at a relatively constant radius then the radius should be entered as zero and any angular motions are excluded from the feedrate calculations. The feedrate will be entirely based on the xyz motions. If the angular changes significantly impact the cutting rate then it is up to the CAD system to slow down the feedrate based on the geometry of things to obtain the desired cutting rate. Inverse Time Feedrate mode is often used for this where the GCode basically specifies the Time each motion segment should take to be executed.

The exception to this is any motion where there is no xyz motion at all (pure angular motion). In this case the feedrate specifies the rate in degrees/min.

Does the DRO in KMotionCNC for the A Axis now reflect degrees or is it still in inches?

Whenever "Degrees" is selected then the Axis will be commanded in degrees and the DRO will display degrees.

Do the Step Response values in KMotion software effect these settings?

Not exactly sure what you mean here. But basically no. The KMotion Step Response Screen always functions in units of counts and seconds.

HTH
Regards

[HLKTech]

Hi HLKTech,

Your calculation looks correct to me. How far is it off? If you are confusing quadrature transitions with quadrature cycles the the result would be off by a factor of 4.

That would depend on the capabilities of your system. Use the KMotion Step Response Screen to test/verify what works well.

The radius settings affect the feedrate calculations. For situations such as engraving on a cylinder (constant radius) where the cylinder rotates and there is also a linear axis along the cylinder, then a simple feedrate can be specified and KMotion is able to plan the rotation and linear motion in a way to maintain the feedrate at the tool tip.

For configurations that do not operate at a relatively constant radius then the radius should be entered as zero and any angular motions are excluded from the feedrate calculations. The feedrate will be entirely based on the xyz motions. If the angular changes significantly impact the cutting rate then it is up to the CAD system to slow down the feedrate based on the geometry of things to obtain the desired cutting rate. Inverse Time Feedrate mode is often used for this where the GCode basically specifies the Time each motion segment should take to be executed.

The exception to this is any motion where there is no xyz motion at all (pure angular motion). In this case the feedrate specifies the rate in degrees/min.

Whenever "Degrees" is selected then the Axis will be commanded in degrees and the DRO will display degrees.

Not exactly sure what you mean here. But basically no. The KMotion Step Response Screen always functions in units of counts and seconds.

HTH
Regards

Thank you Tom. All is working well with the new axis. The problem was with the acceleration being too fast.

We appreciate your help.
Setting up a 5th axis now, so will most certainly have a few more questions then.

Thank you again.